For more information, see the conference website.

The APS March Meeting includes many THz talks and symposia with physics, materials, and biophysics applications. For more information, see the detailed conference website at:

http://www.aps.org/meetings/march/

For more information, see the conference website.

More information will become available on the IRMMW-THz 2011 website.

The APS March Meeting includes many THz talks and symposia with physics, materials, and biophysics applications. For more information, see the detailed conference website at:

http://www.aps.org/meetings/march/

The 29th PIERS 2011 in Marrakesh, Morocco
20-23 March, 2011

PIERS provides an international forum for reporting progress and recent advances in all aspects of electromagnetics. Spectra range from statics to RF, microwave, photonics, and beyond. Topics include radiation, propagation, diffraction, scattering, guidance, resonance, power, energy and force issues, and all applications and modern developments. Potential session organizers are welcome to propose special technical topics by filling out the PIERS survey.

PIERS Suggested Topics:
1 Electromagnetic theory
2 Computational electromagnetics, hybrid methods
3 Spectra, time, and frequency domain techniques
4 Fast iteration, large scale and parallel computation
5 Transmission lines and waveguide discontinuities
6 Resonators, Filters, interconnects, packaging, MMIC
7 Antenna theory and radiation
8 Microstrip and printed antennas, phase array antennas
9 RF and wireless communication, multipath
10 Mobile antennas, conformal and smart skin antennas
11 Power electronics, superconducting devices
12 Systems and components, electromagnetic compatibility
13 Nano scale electromagnetics, MEMS
14 Magnetic levitation, transportation and collision avoidance
15 Precision airport landing systems, GPS
16 Radar sounding of atmosphere, ionospheric propagation
17 Microwave remote sensing and polarimetry, SAR
18 Subsurface imaging and detection technology, GPR
19 Active and passive remote sensing systems
20 Electromagnetic signal processing, wavelets, neural network
21 Rough surface scattering and volume scattering
22 Remote sensing of the earth, ocean, and atmosphere
23 Scattering, diffraction, and inverse scattering
24 Microwave and millimeter wave circuits and devices, CAD
25 Optics and photonics, gyrotrons, THz technology
26 Quantum well devices, microwave photonic systems, PBG
27 Medical electromagnetics, biological effects, MRI
28 Fiber optics, optical sensors, quantum computing
29 Biological media, composite and random media
30 Plasmas, nonlinear media, fractal, chiral media, LHM
31 Constitutive relations and bianisotropic media
32 Moving media, relativity, field quantization, and others

For more information, see the PIERS 2011 Marrakesh Website, and the local PIERS 2011 Marrakesh Organizers Website.

SOLEIL, St Aubin (France)

November 22nd-23rd 2010

The goal of the workshop is to gather a broad international community of users in the field of gas phase molecular spectroscopy, from the THz to the VUV range, around the French Synchrotron SOLEIL. It will emphasize the needs and potential collective actions related to this cross-disciplinary field with applications in astrophysics, astrochemistry, biology and atmospheric photodynamics. In particular, several talks and discussions will be centred on recent experimental developments and striking results obtained on the THz AILES and VUV DESIRS beamlines of SOLEIL, as well as on the synchrotron facilities BESSY (Berlin), Swiss Light Source (Villigen, Switzerland) and the Canadian Light Source (Saskatoon, Canada). Another part of the workshop will be dedicated to laboratory sources complementary to synchrotron sources so that a broad panel of spectroscopic tools is presented. Finally, theoretical and analytical methods for interpreting dense and complex spectra will also be presented.

Our aim is to provide the spectroscopy community with a better knowledge of the possible new experimental and theoretical developments around synchrotron and laboratory sources.

Even though the workshop is organized by the French research network “Spectroscopie moléculaire” (GdR SpecMo) and the French synchrotron SOLEIL, we want to enlarge its scope to the international community. Therefore, the workshop language will be English. We also would like to encourage the participation of young scientists.

Confirmed Speakers: P. Asselin (LADIR, Paris), A. Bodi and S. Albert (SLS, Villigen, Switzerland), S. Boyé-Péronne (ISMO, Orsay), N. De Oliveira (SOLEIL), F. Gaie-Levrel (SOLEIL), G. Garcia (SOLEIL), R. Georges (IPR, U Rennes), Th. Giesen (U. Koeln), M. Goubet (PhLAM, U Lille), L. Margulès (PhLAM, U Lille), N. Picqué (U Paris 11), O. Pirali (SOLEIL), E. Rühl (FU Berlin), J. Vander Auwera (ULB, Bruxelles), L. Tchang-Brillet (LERMA, U Paris 6), D. Tokaryk (Canadian Light Source, U New Brunswick), H. Tran (LISA, CNRS et U. Paris 7 et 12), W. Ubachs (LCVU, Amsterdam), V. Zéninari (GSMA, U Reims)

Local Organisation: Frédérique Fraissard, Sylvie Koguc, Jean-Marc Lucacchioni, Margot Perez, and Isabelle Quinkal (SOLEIL)

Contact : Conf-SPECMO-SOLEIL@synchrotron-soleil.fr

Scientific committee: Isabelle Kleiner, Martin Schwell (LISA, U Paris 7 & 12), Vincent Boudon (ICB, U. Bourgogne), Pascale Roy, Laurent Nahon (Synchrotron SOLEIL), Dolorès Gauyacq (ISMO, Orsay)

For more information, see the conference website.

The 2nd International Workshop “THz Radiation: Basic Research and Applications“ (TERA’2010) will be held in historical city Sevastopol, Crimea, Ukraine, from September 12 to September 14, 2010. TERA’2010 will provide a forum for experts in a wide area of optical and microwave physics and photonics.

Terahertz is unique in its ability to penetrate through nearly any material without causing biological harm. This will allow scanning for weapons, detecting hidden explosives, pinpointing the location of skin cancer during surgery, and a host of other exciting applications. The workshop will cover frontiers in terahertz physics and applications. Its characteristic feature is a stronger emphasis on the mathematical and physical aspects of the researches, together with a detail analysis of the application problems. The technical program consists of invited lectures and regular contributed papers.

Previous meetings provided in 2008 (TERA2008, Ukraine) and 2009 (special NATO ARW Workshop TERA-MIR, Turkey) have confirmed our expectations. They have shown the necessity of holding the annual forum and growth of participant number. TERA2010 will be organized in series with more wider events: 5th International Conference on Advanced Optoelectronics and Lasers, CAOL’2010 and 10th Int. Conference on Laser and Fiber Optics Networks Modeling, LFNM’2010 which gives an opportunity to gather many experts from the FSU and neighboring countries of the East and South Europe, Asia, and overseas.

TERA’2010 TOPICS
• THz sources and detectors
• Intersubband transport and optics
• Intersubband lasers and detectors
• THz imaging and remote sensing
• Inversionless lasers
• Material properties at THz frequencies
• Methods and strategies for THz generation and detection
• Novel materials for THz applications
• THz waveguiding and localization
• Applications in biology and medical diagnosis
• THz metamaterials
• Detection of explosives and dangerous substances
• Nonlinear THz optics
• Integration of THz with optical fibers

Important dates:
Deadline for submission of 3 pages camera-ready papers is June 1, 2010 (by e-mail).
Author notification date: June 20, 2010
Postdeadline paper may be submitted up to August 10, 2010

For more information, see the TERA 2010 Website.

The 5nd International Conference on Advanced Optoelectronics and Lasers (CAOL’2010) will be held in Sevastopol, Crimea, Ukraine, September 10 – 14, 2010. CAOL’2010 will provide a forum for experts in a wide area of laser physics and optoelectronics. The previous conferences were successfully provided in 2003, 2005 and 2008 in Crimea, and in 2006 in Guanajuato, Mexico.

Information on the previous international meetings on optoelectronics and lasers can be found in the magazines IEEE/LEOS Newsletters: 4-1999, 4-2000, 4-2001, 3-2004 2-2006, 2-2009 and IEEE Antennas and Propagation Magazine: 4&5-1998, and 3-2001. The conference will cover wide frontiers in laser physics, nanotechnology, new materials, nonlinear optics and optical communications. Its characteristic feature is a stronger emphasis on the mathematical, physical and technological aspects of the researches, together with a detail analysis of the application problems. The technical program traditionally consists of invited lectures and regular contributed papers.

Conference will be held in collaboration with IEEE/Photonics Society, Regional IEEE Chapters, OSA and SPIE.

CAOL’2010 TOPICS
Physics of advanced and novel lasers
Nonlinear optic materials and devices
Solid-state, liquid and gas lasers and applications
High-speed optics and photonic links
Semiconductor lasers
PBG and photonic crystal devices
Laser resonators and beam propagation
Structurated fibers and fiber lasers
THz generation, detection, guidance and control
Optical communications. Integrated and nonlinear waveguide photonics
Laser biomedicine and chemistry
Liquid Crystals in optics and photonics
Nanophotonics, plasmonics, near field optics
Quantum information
Metamaterials, optical invisibility, and transformation optics
Optical measurement and instrumentation
Silicon nano-photonics: nano-optoelectronics, nano-antenns, nano sources and confined light emitters
Organic coherent optics and bio-photonics

Accompanying event: 2nd International Workshop “THz Radiation: Basic Research and Applications“ (TERA’2010)

For more information, see the CAOL’2010 Website.

The following is a representative list of topics covered at the conference:

• IR, THz, and MMW Sources and novel generation schemes
• Laser driven THz Sources
• Quantum Cascade Lasers
• Gyro-Oscillators and Amplifiers, Plasma Diagnostics
• Free Electron Lasers and Synchrotron Radiation
• Detectors and Receivers
• Instruments, Devices and Components
• MMW systems, Transmission Lines and Antennas
• Ultra-fast Measurements
• Plasma Diagnostics
• IR, THz and MMW Spectroscopy and Material Properties
• Ultra High Speed MMW Digital Devices
• MMW and Submillimeter-Wave Radar and Communications
• IR, THz and MMW Astronomy and Environmental Science
• IR, THz and MMW Imaging and Remote Sensing
• Applications in Art Conservation studies
• Applications in Biology and Medicine
• Applications in Security and Defence
• IR, THz and MMW R&D and market trends

Participants to IRMMW-THz 2010 Conference that wish to contribute to the conference program are required to send a One Page Summary of their presentation electronically from February 1 to April 2, 2010 using the web site submission form. The submitted Summary will undergo an internal review process and Notification of Acceptance will be sent on May 21, 2010. Once the Summary is accepted for the Conference, Authors are invited to prepare a Two Page paper to be included in the Conference Proceedings and to be published electronically by IEEE. Final paper submission deadline is June 25, 2010.

For more information, see the IRMMW-THz 2010 web site.

Commercial terahertz spectrometers operating at frequencies from 0.1 to 3.0 THz are widely used in academic and industrial research labs. Most time-domain terahertz systems are based on terahertz generation via photoexcitation of photoconductive switches with femtosecond lasers and require highly efficient terahertz emitters in order to achieve good system performance. However, for many terahertz sources, long-term stability and high conversion efficiency is still lacking.

Two new concepts for terahertz generation overcome these problems. The first is a biased large-area photoconductive emitter with high conversion efficiency and the second concept is a new approach to the generation of intense terahertz radiation based on the photo-Dember effect—a technique that does not require a bias voltage. The large-area design of both concepts enables scalability toward high terahertz electric fields, enabling both high signal-to-noise ratios and short acquisition times.

Multiplexed terahertz emitters can be based on the principle of a photoconductive switch (a) or lateral photo-Dember currents (b).

Continue reading the full article by THOMAS DEKORSY, JURE DEMSAR, STEPHAN WINNERL, MATTHIAS BECK, and GREGOR KLATT at OptoIQ.com.

The International Symposium “Terahertz Radiation: generation and applications” is devoted to the discussion on basic research and applications of terahertz (THz) radiation.
Organizers of the Symposium

Budker Institute of Nuclear Physics Siberian Branch of Russian Academy of Sciences (BINP SB RAS), Lomonosov Moscow State University (MSU), Novosibirsk State University (NSU), and Institute of Applied Physics RAS (IAP RAS) (Nizhny Novgorod) with the support from the Russian Foundation for Basic Research, Ministry of Education and Science of the Russian Federation.

Co-chairs of the Symposium Organizing Committee:
Kulipanov G.N., BINP SB RAS, Novosibirsk
Litvak A.G., IAP RAS, Nizhny Novgorod

Deputy Co-chairs:
Knyazev B.A., NSU, Novosibirsk
Shkurinov A.P., MSU, Moscow

Organizing Secretary:
Mezensteva L.A., BINP SB RAS, Novosibirsk

Symposium topics

1. Basis of generation of terahertz radiation. Pulsed and continuous wave THz sources, including generators using electron beams.
2. Detection of terahertz radiation. Recording and processing of terahertz images. Terahertz tomography and holography. Spectroscopy and metrology in terahertz frequency range.
3. Study of materials (including nano- and meta-materials) using terahertz radiation.
4. Pulsed terahertz radiation of high intensity and its applications to study and control the ultrafast processes in physics, chemistry, and biology. Pulsed terahertz spectroscopy.
5. Terahertz microscopy, including near-field terahertz microscopy.
6. Development of fundamental principles of terahertz lidar technique and terahertz communication with terahertz radiation.
7. Terahertz non-destructive detection and development of security aimed systems. Biomedical applications of terahertz radiation.

The Organizing Committee is ready to consider suggestions on introduction of additional topics to the Symposium Program.

Symposium Venue

Symposium sessions will take place at Budker Institute of Nuclear Physics SB RAS and will include the 40-minute plenary lectures, 20-minute oral talks and poster presentations.

Publications:

Symposium Proceedings with three-page papers will be published by the beginning of the Symposium. The Proceedings will be officially registered as a scientific publication, with assignment of an ISBN code.

Selected papers presented at the Symposium will be published in special issues of the following journals:
- Radiophysics and Quantum Electronics,
- Vestnik Novosibirsk State University. Physics,
- International Journal of Infrared, Millimeter, and Terahertz Waves.

Exhibitions:

Exhibitions of equipment for experts in the THz radiation field will be organized within the framework of the Symposium. Applications for exhibits should be submitted to the Organizing Committee.

Symposium program structure:

From Monday, July, 26 till Wednesday, July, 28: plenary lectures, oral talks and poster sessions.
In the evening of Wednesday, July, 28: departure for Altai, the actual place to be specified later (arrival early Thursday, July, 29). The cost of the Altay trip is not covered by the registration fee. The detailed program of the trip and its cost will be given at the Symposium site by the end of February.
Thursday July, 29 to Saturday, July, 31: stay in Altai and “round table” sessions in the evenings.
Sunday, August, 1 2010: Coming back from Altai (arrival in Novosibirsk by night).

Scientific School-Workshop
“Terahertz Radiation: generation and application”

The Scientific School-Workshop program will include 40-minute lectures by leading Russian and foreign scientists on actual topics of terahertz radiation generation and their applications, special reports on recent research results and oral reports by the School students at a special session. The program of the Scientific School-workshop is being created now.

A state standard Certificate will be given after the School.

For more information, see the Symposium Website.

You are creative, imaginative and experienced with fs-impulse lasers, ultrashort pulse optics for light or infrared and terahertz waves. You feel at home in the field of Terahertz Time-Domain Spectroscopy or a comparable field of work. You know how to design electro-optical assembly groups for generating and detecting terahertz impulses using ultrashort pulse lasers and you have extensive knowledge in the field of beam conditioning and the integration of the required components within a measurement system. Further experience in the following fields will be an advantage:

• coupling of ultra short lasers into glass fibres
• mechanical and optical construction, for example with Solid-Works

You will find an inspiring field of work, offering creative freedom in a pleasant environment of a straightforward family business that cooperates with partners in more than 40 countries. We are looking forward to your application.

Please, send your documents, including your salary requirements and your earliest starting date, by e-mail to info@score-personal-services.de. Our assigned consultant, Dipl.-Ing. Manfred Schrage, will respect any restriction notes implicitly.

Name of Employer:
Automation Dr. Nix GmbH & Co. KG
Contact Email:
info@score-personal-services.de
URL:
www.automation.de
Country:
Germany
City:
Cologne

A team in the Advanced Diagnostics & Therapeutics (AD&T) Initiative at the University of Notre Dame has been awarded a grant of $359,281 for the development of a room-temperature, portable terahertz (THz) imaging system from the National Science Foundation (NSF) via the Integrative, Hybrid and Complex Systems (IHCS) program.

Led by Research Assistant Professor Lei Liu, Associate Professor Grace Xing and Professor Patrick Fay of the Department of Electrical Engineering, the team is working to develop an imaging device and nano-scale detectors that would create such a system, one that would more affordably capture high-quality images in real time at room temperature.

According to Liu, who will design the overall system and test the THz detectors developed by the team, the entire system would operate like a camera but in the submillimeter-wave and THz range of the electromagnetic spectrum — between radio frequency and the optical region.

“The development of such a system is important, not only because it does not require extensive cooling equipment but also because of the potential applications it enables across a variety of fields,” he said.

THz waves (and subsequent imaging systems) are ideal for medical applications because they are non-ionizing, meaning they do not damage living tissue in the same way that X-rays can. They are able to provide high-resolution images because of their short wavelengths, and this wavelength range also provides the ability to detect differences in tissue density more effectively than X-rays. For example, even though breast magnetic resonance imaging machinery does not use ionizing radiation, the units themselves are bulky and do not always provide accurate images. The system that the Notre Dame researchers are developing shows promise in enhanced cancer diagnostics, the early identification of disease biomarkers and increased quality of pharmaceuticals, detecting impurities or defects.

In addition, submillimeter-wave and THz waves can penetrate fabrics, plastics and cardboard, so they can easily be used in security applications to reveal concealed weapons or devices. In military applications, they could also prove useful by more effectively targeting specific ranges of materials or objects, as well as being able to accurately sense traces of explosive elements.

The goal of the IHCS program is to design, develop and implement novel complex and hybrid systems that lead to innovative engineering solutions for a variety of fields including, but not limited to, healthcare, medicine, the environment, communications, disaster mitigation, homeland security, transportation, manufacturing, energy and smart structures.

Established in 2008, AD&T is an interdisciplinary research initiative focused on developing diagnostic and therapeutic technologies at the smallest molecular scales to address a diverse set of health and environmental challenges.

For more information about research initiatives within the AD&T, visit http://advanceddiagnostics.nd.edu.

Source: South Bend Tribune.

It’s a sign of the times when the speed of electrons moving through wires is seen as pedestrian, but that’s increasingly the case as technology moves towards the new world of optical communication and computing. Optical communication systems that use the speed of light as the signal are still controlled and limited by electrical signaling at the end. But physicists have now discovered a way to use a gallium arsenide nanodevice as a signal processor at “terahertz” speeds that could help end the bottleneck.

The new discovery, made by researchers at Oregon State University (OSU), the University of Iowa and Philipps University in Germany, has identified a way in which nanoscale devices based on gallium arsenide can respond to strong terahertz pulses for an extremely short period, controlling the electrical signal in a semiconductor. The devices can be used as optical switches, replacing wires with emitters and detectors that can function at terahertz speeds.

Yun-shik Lee, an associate professor in the OSU Department of Physics, says the first applications of this type of technology would probably be in optical communications of almost any type – video, audio or others. However, the ultimate application could be quantum computing, in which computers would be orders of magnitude faster than they are now, working with a different physical and logic basis, not even using conventional transistors. Among other uses, Lee says their extraordinary speeds would make them extremely valuable for secure codes and communications.

“This could be very important,” Lee said. “We were able to manipulate and observe the quantum system, basically create a strong response and the first building block of optical signal processing.”

The team’s research appears in the journal, Solid State Electronics.

Source: GizMag.

Project: Inquiries are invited to fill an immediate opening for a 1 year post-doctoral research position with a possible additional year renewal to perform DHS-funded research in time-domain THz imaging at NIST. The successful applicant will reconfigure a femtosecond pulsed THz imaging system to perform bi-directional reflection distribution function (BRDF) measurements of materials. This will entail optical design and implementation of data acquisition code to perform and analyze reflection measurements as a function of polarization and angle. The position will be physically located on the NIST Gaithersburg, MD campus.

This work is currently funded and we seek to immediately identify qualified applicants to fill this position.

The successful applicant must have a PhD in chemistry, electrical engineering, physics, or a related field and several years of research experience in ultrafast laser spectroscopy/phenomena, THz science and technology and a strong physics or applied optical physics background.

If you are interested in this position, please submit your CV to Dr. Heilweil as soon as possible by email for your application to be considered.

Dr. Edwin J. Heilweil
edwin.heilweil@nist.gov
Optical Technology Division
National Institute of Standards & Technology
Gaithersburg, MD 20899-8443
Tel: 301-975-2370

Full Time

The appointment will be on UCL Grade 6. The salary range will be £25,683 per annum, inclusive of London Allowance.

The Photonics group within the Department of Electronic and Electrical Engineering seek to recruit two Marie Curie Trainees in the area of THz Photonics, each for a period of three years. It is hoped that both trainees will start in September 2010.

One trainee will carry out cutting edge research in to the design and characterization of optimized semiconductor based antenna integrated 1.55ìm travelling wave uni-travelling carriers photomixers for millimeter-wave to THz signal generation for applications ranging from non-destructive detection to wireless high data rate transmission. Particular attention will be put on optimizing the output power and saturation of the device.

The other trainee will carry out cutting edge research in to the design, development and characterization of integrated heterodyne THz systems, based on dual lasers and integrated phase lock loops. Such a source offering tuneability should provide THz signal generation for applications ranging from non-destructive detection to wireless high data rate transmission. Particular attention will be put on developing the agility of the system and demonstrating its tuning range.

The successful candidates will have a Masters degree in Physics or Electronic Engineering. The successful candidates will also meet the mobility requirements of Marie Curie Actions and the other criteria as detailed in the Further Particulars document.

For further details about the vacancy and how to apply on line please go to http://www.ucl.ac.uk/hr/jobs/ and search on Reference Number 1147238.

Informal enquiries regarding the position should be sent to Dr Cyril Renaud (c.renaud@ee.ucl.ac.uk).

Closing Date: 31/07/2010 by 5.00pm

Infrared (IR) and terahertz (THz) light is extremely sensitive to different material properties and thus can be used for characterizing chemical composition, crystal structures as well as conduction properties. However, due to the diffraction-limited spatial resolution, conventional techniques cannot be applied to image local material properties in nanostructures or nanodevices This problem can be tackled by near-field optical microscopy that uses a sharp tip to focus the light to nanoscale spot sizes, thus allowing to generate two-dimensional (2D) maps of surfaces with a spatial resolution far below the diffraction limit. “By developing novel near-field techniques paired with computed image reconstruction, we now want to develop three-dimensional (3D) near-field microscopy. This shall allow to image the inside of nanostructures with IR and THz light, in a similar way as Computed Tomography (CT) sees inside the human body” says Rainer Hillenbrand.

Rainer Hillenbrand earned his PhD from the Technische Universität München for research and development in optical near-field microscopy. From 2003 to 2008 he was Head of the Independent Junior Research Group “Nano-Photonics” at the Max Planck Institute of Biochemistry, which was funded within a Nanofutur grant awarded by the German Federal Government for Education and Research. As anticipated by the Nanofutur project, in 2007 the spin-off company Neaspec GmbH was founded with the mission to develop IR and THz near-field microscopes for the research laboratory and to promote their industrial applications. Since 2008 Rainer Hillenbrand continues his scientific research activities as an Ikerbasque Research Professor (Basque Foundation for Science) and Nanooptics group leader at CIC nanoGUNE in San Sebastian, Spain.

Rainer Hillenbrand is already the forth winner of an ERC grant within CeNS in 2010: The other grantees are Philipp Tinnefeld, Dieter Braun and Thomas Klar. Furthermore, two other CeNS members were awarded with this prestigious grant already in 2009: Jens Michaelis (LMU Munich) and Matthias Schneider (at that time at the University of Augsburg).

ERC Starting Independent Researcher Grants (ERC Starting Grants) aim to support up-and-coming research leaders to establish or consolidate their independent research group. Being a very competitive program, proposals are assessed only in terms of their scientific excellence, and less than 10% of the applications were accepted in the 2009 call.

Source: NanoWerk News

The new, all-optical system, using terahertz (THz) wave technology, has great potential for homeland security and military uses because it can “see through” clothing and packaging materials and can identify immediately the unique THz “fingerprints” of any hidden materials.

Terahertz waves occupy a large segment of the electromagnetic spectrum between the infrared and microwave bands which can provide imaging and sensing technologies not available through conventional technologies such as x-ray and microwave.

“The potential of THz wave remote sensing has been recognized for years, but practical application has been blocked by the fact that ambient moisture interferes with wave transmission,” says Xi-Cheng Zhang, Ph.D., director of the Center for THz Research at Rensselaer.

Dr. Zhang, the J. Erik Jonsson Professor of Science at Rensselaer, is lead author of a paper to be published next week in the journal Nature Photonics. Titled “Broadband terahertz wave remote sensing using coherent manipulation of fluorescence from asymmetrically ionized gases,” the paper describes the new system in detail.

The “all optical” technique for remote THz sensing uses laser induced fluorescence, essentially focusing two laser beams together into the air to remotely create a plasma that interacts with a generated THz wave. The plasma fluorescence carries information from a target material to a detector where it is instantly compared with material spectrum in the THz “library,” making possible immediate identification of a target material.

“We have shown that you can focus a 800 nm laser beam and a 400 nm laser beam together into the air to remotely create a plasma interacting with the THz wave, and use the plasma fluorescence to convey the information of the THz wave back to the local detector,” explains Dr. Zhang.

Repeated terrorist threats and the thwarted Christmas Eve bombing attempt aboard a Delta airline heightened interest in developing THz remote sensing capabilities, especially from Homeland Security and the Defense Department, which have funded much of the Rensselaer research.

Because THz radiation transmits through almost anything that is not metal or liquid, the waves can “see” through most materials that might be used to conceal explosives or other dangerous materials, such as packaging, corrugated cardboard, clothing, shoes, backpacks and book bags.

Unlike x-rays, THz radiation poses little or no health threat. However, the technique cannot detect materials that might be concealed in body cavities.

“Our technology would not work for owners of an African diamond mine who are interested in the system to stop workers from smuggling out diamonds by swallowing them,” Dr. Zhang says.

Though most of the research has been conducted in a laboratory setting, the technology is portable and eventually could be used to check out backpacks or luggage abandoned in an airport for explosives, other dangerous materials or for illegal drugs. On battlefields, it could detect where explosives are hidden.

The fact that each substance has its own unique THz “fingerprint” will show exactly what compound or compounds are being hidden, a capability that is expected to have multiple important and unexpected uses. In the event of a chemical spill, for instance, remote sensing could identify the composition of the toxic mix. Since sensing is remote, no individuals will be needlessly endangered.

“I think I can predict that, within a few years, the THz science and technology will become more available and ready for industrial and defense-related use,” predicts Dr. Zhang.

Source: PhysOrg.com.

At the Graduate School of Engineering Science in Osaka Univ., Japan, we are seeking a candidate for a postdoctoral fellowship for the duration of 30 months, starting Oct. 1, 2010. The successful applicant will work on a topic of high-precision THz spectroscopy and THz frequency metrology based on frequency comb in optical and THz regions or asynchronous-optical-sampling method. Candidates must have a PhD (or equivalent) and have research experience in THz instrumentation and metrology (THz-TDS, CW-THz spectroscopy, THz-QCL, etc), optical frequency metrology (optical comb, laser stabilization, etc), or ultrafast spectroscopy with femtoseocnd laser based on strong backgrounds of laser metrology, spectroscopy, applied optics, applied physics, or electrical engineering. Further information of this recruitment is given online.

Although deadline for the application is Sept. 30, 2010, candidate selection proceeds in order of receipt, and the recruitment is closed when the final candidate is decided.

If you might be interested in the position, please contact Dr. Takeshi Yasui by email
(t-yasui[at]me.es.osaka-u.ac.jp) as soon as possible.

TeraView currently offers a range of the most advanced, cutting edge THz spectrometers in the world. One of TeraView’s leading products, the CW Spectra 400(TM) utilizes the sub-licensed technology. The system generates a continuous wave which has a tunable frequency that is emitted and detected via a set of proprietary, fibre-fed THz photomixers. By the addition of suitable supports, gantries or other units, the CW Spectra 400(TM) is capable of performing spectroscopy and imaging on a range of objects and materials. Under the terms of the Sub-Licensing Agreement, T-Ray Science will collect royalties on the sales of this product and any other products that utilize CW generation in the United States.

According to BCC Research, overall spectroscopy sales in the US are expected to reach $5.2 billion this year, with an average annual growth rate of 7.7%. Furthermore, BCC Research estimates the THz imaging market will be worth $207 million by 2018, with a compound annual growth rate of 37.2% for the period between 2013 and 2018.

“THz technology is different from other methods because one can image things as well as take measurements,” said Thomas Braun, President of T-Ray Science. “We believe that a significant percentage of the THz market will go to CW THz devices due to their relative affordability versus other types of THz instruments. Therefore, CW THz technology is very well positioned to compete in a market that demands mass production, low cost, and portability.”

T-Ray’s Science’s platform THz imaging technology has been shown to have numerous potential applications including homeland security, the detection of explosives and ceramic knives, process control in the paper, plastics, petro chemical and pharmaceutical industries, and medical imaging for detection of skin and other cancers. THz waves are also a safe, accurate, and economical alternative to other scanning methods such as high frequency ultrasound, magnetic resonance imaging, and near-infrared imaging. This emergent technology has the potential to revolutionize the way many diseases are diagnosed, and ultimately cured. Numerous studies have shown that THz imaging can be used to image various cancers of which skin cancer imaging continues to be the focus of T-Ray Science’s research and development.

More About TeraView Ltd.
More About T-Ray Science, Inc.

The 28th PIERS 2010 in Cambridge, USA
5 – 8 July, 2010

PIERS provides an international forum for reporting progress and recent advances in all aspects of electromagnetics. Spectra range from statics to RF, microwave, photonics, and beyond. Topics include radiation, propagation, diffraction, scattering, guidance, resonance, power, energy and force issues, and all applications and modern developments. Potential session organizers are welcome to propose special technical topics by filling out the PIERS survey at http://piers.org/.

SUGGESTED TOPICS:
1 Electromagnetic theory
2 Computational electromagnetics, hybrid methods
3 Spectra, time, and frequency domain techniques
4 Fast iteration, large scale and parallel computation
5 Transmission lines and waveguide discontinuities
6 Resonators, filters, interconnects, packaging, MMIC
7 Antenna theory and radiation
8 Microstrip and printed antennas, phase array antennas
9 RF and wireless communication, multipath
10 Mobile antennas, conformal and smart skin antennas
11 Power electronics, superconducting devices
12 Systems and components, electromagnetic compatibility
13 Nano scale electromagnetics, MEMS
14 Magnetic levitation, transportation and collision avoidance
15 Precision airport landing systems, GPS
16 Radar sounding of atmosphere, ionospheric propagation
17 Microwave remote sensing and polarimetry, SAR
18 Subsurface imaging and detection technology, GPR
19 Active and passive remote sensing systems
20 Electromagnetic signal processing, wavelets, neural network
21 Rough surface scattering and volume scattering
22 Remote sensing of the earth, ocean, and atmosphere
23 Scattering, diffraction, and inverse scattering
24 Microwave and millimeter wave circuits and devices, CAD
25 Optics and photonics, gyrotrons, THz technology
26 Quantum well devices, microwave photonic systems, PBG
27 Medical electromagnetics, biological effects, MRI
28 Fiber optics, optical sensors, quantum computing
29 Biological media, composite and random media
30 Plasmas, nonlinear media, fractal, chiral media, LHM
31 Constitutive relations and bianisotropic media
32 Moving media, relativity, field quantization, and others

For more information, see the PIERS 2010 Cambridge Website.

Please note that application is only possible online at www.igsm.tu-bs.de. The application period will start on 1 July 2010, deadline is 31 August 2010.
Contact Email: igsm-application@web.de

By combining a detector and laser on the same chip to make a compact receiver, the researchers rendered unnecessary the precision alignment of optical components formerly needed to couple the laser to the detector.

The new solid-state system puts to use the so-called “neglected middle child” frequency range between the microwave and infrared parts of the electromagnetic spectrum.

Terahertz radiation is of interest because some frequencies can be used to “see through” certain materials. Potentially they could be used in dental or skin cancer imaging to distinguish different tissue types. They also permit improved nondestructive testing of materials during production monitoring. Other frequencies could be used to penetrate clothing, and possibly identify chemical or biological weapons and narcotics.

Since the demonstration of semiconductor THz quantum cascade lasers (QCLs) in 2002, it has been apparent that these devices could offer unprecedented advantages in technologies used for security, communications, radar, chemical spectroscopy, radioastronomy and medical diagnostics.

Until now, however, sensitive coherent transceiver (transmitter/receiver) systems were assembled from a collection of discrete and often very large components. Similar to moving from discrete transistor to integrated chips in the microwave world and moving from optical breadboards to photonic integrated circuits in the visible/infrared world, this work represents the first steps toward reduction in size and enhanced functionality in the THz frequency spectrum.

The work, described in the current issue (June 27, 2010) of “Nature Photonics,” represents the first successful monolithic integration of a THz quantum-cascade laser and diode mixer to form a simple, but generically useful, terahertz photonic integrated circuit — a microelectronic terahertz transceiver.

With investment from Sandia’s Laboratory-Directed Research and Development (LDRD) program, the lab focused on the integration of THz QCLs with sensitive, high-speed THz Schottky diode detectors, resulting in a compact, reliable solid-state platform. The transceiver embeds a small Schottky diode into the ridge waveguide cavity of a QCL, so that local-oscillator power is directly supplied to the cathode of the diode from the QCL internal fields, with no optical coupling path.

###
The Sandia semiconductor THz development team, headed by Michael Wanke, also included Erik Young, Christopher Nordquist, Michael Cich, Charles Fuller, John Reno, Mark Lee — all of Sandia labs — and Albert Grine of LMATA Government Services, LLC, in Albuquerque. Young recently joined Philips Lumileds Lighting Co., in San Jose, Calif.

The paper is available online at: http://dx.doi.org/10.1038/NPHOTON.2010.137 . Abstracts are available to everyone; full text only to subscribers.

We are looking for ambitious young scientists with a world-class research project at the forefront of Optics and Photonics, including fundamentals and applications. Areas of special interest include, but are not limited to, Nanophotonics, Biophotonics, Quantum Optics, and THz Photonics. The NEST program offers outstanding start-up packages for equipment and personnel.

Applicants are requested to send a brief statement of interests and research plans, the full curriculum vitae, and the contact information for at least three references, to:

Search Committee: NEST
ICFO-Institute of Photonic Sciences
Mediterranean Technology Park
Av Canal Olimpic s/n
08860 Castelldefels (Barcelona), Spain
icfojobs@icfo.es

Inquires for further information should be addressed to Professor Lluis Torner, ICFO director, at: director@icfo.es.

The GaN detector forms a so-called plasma wave of the electrons, in which the electron density is fluctuated as a wave. The plasma wave resonates with the incident THz wave, which is detected as an electric signal at the GaN transistor. The use of GaN with high electron velocity effectively increases the amplitude of the plasma wave and the extracted electric signal. The detector uses the gate electrode itself as a dipole antenna free from the loss in the transmission lines. In addition, the source and the drain electrodes of the GaN transistor are designed to work as parasitic elements for the antenna, which effectively confine the incident THz wave in the vicinity of the gate. Note that the employed metal-oxide-semiconductor (MOS) gate structure reduces the gate leakage current suppressing the leakage of the plasma wave around the gate antenna. The choice of the material together with a novel antenna structure successfully increases the sensitivity of the THz detector.

The fabricated THz detector using Panasonic’s proprietary GaN technologies achieves a very high sensitivity of 1100 V/W at room temperature, while a conventional detector utilizing thermal conversion requires cooling of the device down to -270°C to maintain high enough sensitivity. The developed GaN-based THz detector free from such cooling systems can make the THz systems very compact keeping high sensitivity.

Applications for 9 domestic and 1 overseas patents have been filed. These research and development results have been presented at 68th Device Research Conference, held in South Bend, Indiana, U.S. from June 21 to 23, 2010.

Source: Panasonic.

“At lower frequencies, in the Terahertz range, which is situated between the frequencies of the infrared light and microwave radiation in the electromagnetic spectrum, far more complex motions take place involving motions of whole water molecules relative to each other”, explains Terahertz specialist Prof. Havenith-Newen. “In particular, these motions involve closing and breaking of the three dimensional hydrogen bond network of water, which interconnects water molecules and is responsible for the unique properties of water.”

Observations of this kind have become feasible only lately with the development of advanced laser light sources.

Studies performed at the RUB lead to the discovery of an unexpectedly long ranged influence of biologically relevant solutes, such as sugars and proteins, on the motions of water, the so-called “Terahertz-dance” of water (“Dissecting the THz spectrum of liquid water from first principles via correlations in time and space”). In the vicinity of the molecule, water motion is highly ordered: “While water molecules usually behave like disco dancers, in the proximity of biomolecules they perform a minuet”, says Prof. Havenith-Newen. However, until now a detailed explanation of this unexpected phenomenon was not available.

Dance of water molecules.

The choreography of water

The underlying vibrational motions between water molecules are extremely complex. So far it was not possible to explain the experimental result with a molecular mechanism. In a joint effort, scientists of both departments performed molecular dynamics simulations of water, which in contrast to conventional approaches, are not based on empirical models for the interactions between molecules, but employ ab initio calculations. For the first time such simulations have been carried out on a scale which allows for statistically meaningful statements about the comparably slow vibrational motions between the water molecules. These extensive calculations were supported by the Leibniz Computing Center in Garching near Munich, which granted access to computational resources on the national supercomputer HLRB2. The use of newly developed analysis methods yielded a precise description of the THz vibrations in water as a correlated motion of many water molecules: a sort of motion of water droplets within the water. “Therefore we have uncovered ‘the choreography of pure water’ at low frequencies”, says Prof. Marx.

Perturbed choreography

If another substance, such as a protein, is dissolved in water, it “perturbs” this choreography at its interface. This allows for a qualitative understanding of the experimental results using THz spectroscopy. “The correlated motions of water molecules at THz frequencies exhibit entirely new characteristics, which are significantly different from the well-known infrared vibrations of the chemical bonds within a molecule”, explains Prof. Marx. As this study shows, the latter are well described as localized vibrational motions within single molecules as well as direct neighbors. This is in stark contrast to the choreography of the THz dance of water: Here, many water molecules, connected only indirectly via hydrogen bonds, move together in a concerted motion in space and time. It is the change of this correlation, evoked by the biomolecule-water interface, which is detected by THz spectroscopy and used for technological applications.

Source: NanoWerk.com

The goal of this workshop is to bring together researchers working in the field of THz spectroscopy, mainly of solids. This includes spectroscopy using short-pulse, high-power sources as well as broad-band sources, but also microscopy and imaging. A further focus will be THz spectroscopy in high magnetic fields (including high-frequency / high-field ESR).

A motivation for this workshop relates to the fact that at FZD the short-pulse THz/infrared free-electron laser FELBE is being operated as a user facility (funded as a transnational access facility in the EU project ELISA), and is in fact connected to the Dresden pulsed high-magnetic field laboratory HLD (funded as a transnational access facility in the EU project EuroMagNET II). In addition, it is planned to extend the facilities with an accelerator-based broad-band high-power source of coherent THz radiation within the next few years. A further important aspect relates to the fact that presently a new THz free-electron laser (FLARE) is being constructed at the high-magnetic field lab in Nijmegen.

The THz workshop will actually take place the first two days (14-15 June), while the third day (16 June) will be devoted to a EuroMagNET II user meeting, covering all aspects of high-magnetic-field experiments (not only spectroscopy). The first day (14 June) represents a FELBE user meeting as well.

More information at www.fzd.de/thz2010 .

It is a single cork, from Portugal, where 320 million pounds of bottle stoppers are produced every year. The billion-dollar cork industry is in trouble from a chemical that ruins the taste of wine. That is why physicist John Federici is bombarding the cork with terahertz rays, which can detect minute traces of the chemical.

But to Federici and other researchers at NJIT, these X-ray-like waves also may offer a first line of defense against suicide bombers and biological terrorists.

Bad corks, terrorism, natural disasters — it is all one to the scientists at NJIT, one of the top homeland security research universities in the country, where $100 million a year in anti-terrorism research translates into products with a vast range of applications.

John Federici, Distinguished Professor of Physics, poses with a Terahertz Interferometric Imaging Array in his lab at NJIT. The array uses terahertz rays to see through clothing and containers to detect concealed objects in real time. As the technology is improved Federici says it can be used in defense against suicide bombers and other terrorist activities.

Since 2004, when the Newark-based university was designated as the site of the New Jersey Homeland Security Technology Systems Center, researchers have applied an “all-hazards” approach to making life in the U.S. a little safer.

“High-tech, low-tech, we can’t afford to overlook any possibility in dealing with mass casualty events,” said center director Donald Sebastian. “You need multiple methods of detection and response. Terrorism comes in many forms; you have to see, smell, taste and analyze everything.”

NJIT has developed a multisystem approach that includes not only advanced detection but communications software that can warn the good guys when the bad guys are up to something.

There are the terahertz, or THz, rays that can leap from detecting bad corks to identifying people who are attempting to smuggle explosives or smallpox into a crowded room. And pattern recognition programs, equally capable of detecting someone lying to immigration officers, buying unusual amounts of suspicious chemicals or casing cars in a mall parking lot.

The research ranges from software for tracing the phone- and internet-usage patterns of home-grown terrorists — which recently helped police track down Faisal Shahzad, charged as the would-be Times Square bomber — to massive blimps designed to hover 12 miles above the Earth, sending back detailed scans of grids covering 500,000 square miles.

“Just because the most recent attacks like the Dec. 25 plane incident or the Times Square car bomber have been primitive and unsuccessful doesn’t mean there aren’t serious, sophisticated enemies probing our weaknesses every day,” said Rep. Bill Pascrell (D-8th Dist.), who last week introduced the bipartisan Weapons of Mass Destruction Prevention and Preparedness Act.

“Intelligence reports predict a significant threat of biological attack on the U.S. by 2013, and we must be prepared,” said Pascrell, a member of the House’s Homeland Security Committee. “The center at NJIT is key to developing a homeland security technology that will help us predict who will attack, what kind of attack, how we prepare, how we respond and how we recover.”

Pascrell helped funnel federal homeland security funding to NJIT. Added to military and National Science Foundation grants over the past five years, the funding placed the New Jersey Institute of Technology in the top 10 engineering universities in the nation, Sebastian said.

PRACTICAL USES
The role of the center is to take existing research and develop workable prototypes. For example, THz technology was isolated about 15 years ago, but applications were limited.
Terahertz waves operate in a similar manner to X-rays and microwaves but on a different bandwidth. Their beauty, said Federici, is that they can scan objects and people without any radiation threat, but are still capable of detecting hidden materials such as explosives and chemicals in amounts as small as parts per billion.

Each chemical emits a signature image that can be captured in real time. That means a person walking through an airport could be scanned without stopping and the imaging system could immediately detect minuscule amounts of anthrax or smallpox.

Federici’s team is developing a cost-effective system that uses a digital video camera to read the scanning results. It would be able to see through barriers such as packaging, corrugated cardboard, walls, clothing, shoes and pill coatings.

Silver foil blocks THz waves, Federici noted, but “it’s hard to walk through a detection system wearing silver foil underpants and not raise suspicion.”

On a purely practical level, life for airline passengers might become a little easier, Sebastian said, because “airport security would immediately know if the shampoo bottle contained benzene or the deodorant stick was really C-4. You could carry as much shampoo as you want because the scanner could identify the contents of the bottle without opening it.”

Scanners and pattern-recognition programs being developed at NJIT — ones that can detect anomalies not only in movement but in facial expressions — would have applications far beyond detecting jihadist plots, experts say.

Smart cameras could track evacuation during disasters such as hurricanes and alert police to potential looters. Smart guns would refuse to fire for anyone but the owner. Computerized noses could sniff and find deadly chemicals.

“I am fascinated by the work at NJIT because it can be applied cross-disaster,” said Charles McKenna, head of the New Jersey Office of Homeland Security and Preparedness. “We are particularly interested in computer profiling, which is much more sophisticated, and quicker, than traditional racial profiling.

“Jihad, Crips, extreme animal-rights activists, it’s all the same: people trying damage the system,” added McKenna. “We need every trick in the book to avert disaster.”

The best prevention systems on the planet, however, aren’t worth much if the word doesn’t get out, Sebastian said.

“None of this works without an integrated communications system connecting local, state and federal agencies — and that we still don’t have in this state or this country,” he said.

“It’s been nine years since 9/11 and we haven’t accomplished that because we are trying to patch rather than replace an inadequate communications system,” Sebastian added. “It’s time to get with the program.”

Source: NJ.com

Scope
The Scope of the workshop is to give an overview over modern terahertz applications and systems. The topics of the presentations cover a wide range of THz generation and detection techniques and, in addition, an interesting variety of applications. Some examples are short pulse systems and radio astronomy.

Workshop Chair
Professor Dr.-Ing. Lorenz-Peter Schmidt
Professor Dr.-Ing. Bernhard Schmauß (Co-Chair)

Local Organising Committee
Martin Nezadal
Dr. Andreas Bräuer

For more information
See the Workshop Website.

“Spectrum Detector’s products are so remarkably complementary to ours that the decision to acquire the company was simple to make, and both sides are very excited to work together”, says Mr. Michel Giroux, president and CEO of Gentec Electro-Optics. Spectrum Detector products cover areas left ignored by the other laser measurement players, and that has been the company’s business model from the beginning. “Classic laser measurement products were already out there, so when we founded Spectrum Detector, we decided to aim wider, and pursue applications that were ignored by others”, mentions Mr. Don Dooley, president and founder of Spectrum Detector. With this idea in mind, and within just a few years, Spectrum Detector managed to develop an extensive line of sensors and instruments for laser and terahertz measurement, and have provided NIST with many custom instruments used as optical calibration transfer standards.

With the addition of Spectrum Detector products, Gentec Electro-Optics will now have measurement solutions for the new and rapidly expanding THz market, ultra-sensitive optical Joulemeters for applications down to femtojoules, instruments for pulse to pulse energy measurements up to 130 kHz and Optical TRAP detectors that act as primary calibration standards, to name a few.

With the acquisition, a new entity has been formed. This new company, named Gentec-EO USA, Inc., employs all the former Spectrum Detector employees, with Mr. Don Dooley as general manager. By creating this entity, Gentec Electro-Optics aims to strengthen its presence in the US.

Source: Photonics Online.

The Terahertz region of the electromagnetic spectrum, which spans from 100 GHz to 10 THz, has attracted a lot of attention in recent years due to the developments in new generation and detection techniques and due to the potential applications in the commercial, scientific, and government areas. As most dielectric materials are transparent at these frequencies and metals are opaque, there has been considerable interest in developing THz technology as an imaging technique for security, environmental and biomedical applications. The course will held topics like Terahertz Photonic Systems, Time-Domain Spectroscopy and Applications, Terahertz Detectors, Antenna and Receiving Architectures, Measurement Principles and Techniques, Heterodyne Systems, THz Imager Radar, THz Space Imaging and Spectroscopy and other its application to the mentioned, security, environmental and biomedical.

The course will present the radiation and propagation characteristics of the electromagnetic waves at terahertz frequencies, will discuss the technological aspects and design criteria for its different components (sources, receivers and antennas), and will model and discuss measurement techniques. The main applications and system architectures for active and passive systems will be analyzed and the more significant parameters compared.

The participants will model the different components of a Terahertz System, with different analytical and software tools and asses their performance in terms of the system response. A realistic system for space or terrestrial applications will be designed and characterized, to check the validity of the methodology.

The course fee is 400 EUR for non-profit institutions and 1000 EUR for profit institutions. Reimbursements will be offered for up to 3 students based on their special course progress and personal needs. The number of participants is limited to 20, so please register as soon as possible.

Lecturers

Prof. Lluis Jofre (course coordinator), Universitat Politècnica de Catalunya (UPC)
Prof. Giles Davies, University of Leeds
Prof. Michael Siegel, University of Karlsruhe
Prof. Antti Räisänen, Helsinki University of Technology (TKK)
Prof. Andrea Neto, Delft University of Technology
Dr. Nuria Llombart (UCM)
Dr. Albert Redó (UB)
Profs. Jordi Romeu, Antoni Broquetas, Francesc Torres, Universitat Politècnica de Catalunya (UPC)

Contents

THz Fundamentals: Electromagnetic radiation and propagation fundamentals.
THz Principles: THz principles and interaction with matter.
THz Sources:THz sources and source design.
THz Receivers:THz Receivers, sensors and receiving architectures.
THz Antennas:THz antennas, principles, topologies and modeling.
THz Measurement techniques:Time and frequency measurement principles and techniques.
THz Applications and systems: Security, environmental and biomedical applications and systems and THz system design.

For course registration or further information the course organizer, Maria Alonso ( esoacourses.bcn@tsc.upc.edu ).

For general information on ESoA 2010, please visit the ACE web site .

Based on their research, these sensors could be used for improving optical sources, detectors and modulators for optical interconnections and for creating biomolecules, such as plastic explosives for the Air Force.

Brongersma’s work is based on the unprecedented ability of nanometallic or plasmonic structures to concentrate light into deep-subwavelength volumes.

“Currently photodetectors, modulators and other chipscale devices are limited in their size by the fundamental laws of diffraction, but with plasmonics, we can make much more compact devices with one to two order of magnitude better performance parameters,” said Brongersma. “As the size of these devices determines their operation speed and power, it’s hard to make much more efficient devices.”

Maier has demonstrated plasmon waveguides on a silicon platform operating in the telecom band, and under AFOSR support he has realized some of the first plasmonic devices operating at THz frequencies.

“The telecom band is important since that’s where data communication is taking place by means of optical fibers and the Internet; the silicon platform is significant because most chips are made of that material,” said Maier. “THz frequencies are vital for their sensing of dangerous substances, including plastic explosives and anthrax.”

The study of plasmonics is bringing these scientists together as each works on fundamentals, information and biotechnology.

“Our team is working on demonstrating plasmon waveguides and cavities for a wide variety of applications spanning the electromagnetic spectrum from the visible to the microwave regime,” said Maier.

Brongersma’s group has worked on the basic concepts behind plasmonics-enabled light concentration and manipulation and is exploring a wide range of applications including faster computer chips, nanostructures synthesis, solar cells, water splitting using photoelectrochemistry, quantum optics and sensing.

Dr. Gernot Pomrenke, a program manager for the AFOSR Physics and Electronics directorate has overseen the research of these scientists for many years and Brongersma credits him with being one of the first program managers in the U.S. to realize the potential importance of plasmonics.

For their outstanding AFOSR-funded experimental and theoretical research in nano-plasmonics and nano-photonics, Brongersma and Maier were awarded the 2010 Raymond and Beverly Sackler Prize in the Physical Sciences.

“We are very excited that our fields of research have gained sufficient visibility for us to become the topics of such a prestigious prize, and we are excited and honored to share the prize equally,” said Brongersma.

The Sackler Prize in the Physical Sciences was established through the generosity of Dr. Raymond and Mrs. Beverly Sackler to encourage dedication to science, originality and excellence by awarding it to outstanding young scientists.

Source: NanoTechWire.

The group is looking for looking for an outstanding PhD candidate to study ultrafast semiconductor materials and related optoelectronic sources of THz and microwaves signals. The PhD work will include characterization of ultrafast semiconductors materials using pump-and-probe optical techniques, the study of THz and microwaves CW generation through optical beating, and the spectroscopy of various materials and devices using the THz sources.
The work is embedded in the MITEPHO training network with the goal to develop compact THz and microwaves sources based on dual frequency lasers and to educate young people in the emerging topic of microwave photonics.

Research Field
Physics – Electronics

Eligible Candidates
The candidate should meet the mobility requirements of Marie Curie Actions:
1. Researchers can be nationals of any EU country (other than France), associated country (Switzerland, Israel, Norway, Iceland, Liechtenstein, Turkey, Croatia, FYR Macedonia, Serbia, Albania, Montenegro, Bosnia & Herzegovina) or International Cooperation Partner country.
2. Researchers must not have resided or carried out their main activity in France for more than 12 months in the last 3 years immediately prior to their recruitment.
3. Candidates living in France for at last two years are not eligible according to the EU mobility requirements.

Application Deadline: 25/06/2010

For further information

http://www.uc3m.es/portal/page/portal/grupos_investigacion/optoelectronics/european_projects/mitepho

Within the project, the successful candidate will be involved in advanced modelling of radiation coupling between free space and wavelength-dimensioned devices, design of practical structures, and optical characterization.

Qualifications
We are seeking a candidate with experience in 3D modelling of photonic elements operating at THz frequencies, advanced THz measurement techniques, and experience with femtosecond fiber laser systems.

Candidates must hold a PhD degree (or equivalent).

Salary and terms of employment
The appointment will be based on the collective agreement with the Confederation of Professional Associations. The allowance will be agreed with the relevant union.

Further information
Further information may be obtained from Professor Peter Uhd Jepsen, tel.: +45 4525 5711.

You can read more about DTU Fotonik on www.fotonik.dtu.dk.

Application procedure
We must have your online application by June 9 2010. Please open the link “apply for this job online” and fill in the application form and attach your application letter, CV and list of publications.The material that should be given consideration in the assessment must be attached.

All interested candidates irrespective of age, gender, race, religion or ethnic background are encouraged to apply.

Details of compact 670 GHz circuit layout Approximately 30-nanometer Indium Phosphide T-gate

Developed at the company’s Simon Ramo Microelectronics Center under a contract with the Defense Advanced Research Projects Agency’s (DARPA) Terahertz Electronics program, this new performance record more than doubles the frequency of the fastest reported integrated circuit.

Dr. William Deal, THz Electronics program manager for Northrop Grumman’s Aerospace Systems sector, detailed the performance of this new TMIC amplifier today at the Institute of Electrical and Electronics Engineers’ (IEEE) International Microwave Symposium being held in Anaheim, Calif. He told fellow scientists that the TMIC amplifier is the first of its kind operating at 670 GHz.

“A variety of applications exist at these frequencies. These devices could double the bandwidth, or information carrying capacity, for future military communications networks. TMIC amplifiers will enable more sensitive radar and produce sensors with highly improved resolution,” said Deal.

His technical paper is available online.

The goal of DARPA’s Terahertz Electronics program is to develop the critical device and integration technologies necessary to realize compact, high-performance, electronic circuits that operate at center frequencies exceeding 1.0 THz. Managed by DARPA’s Microsystems Technology Office, the program focuses on two areas – terahertz high-power amplifier modules, and terahertz transistor electronics.

“The success of the THz Electronics program will lead to revolutionary applications such as THz imaging systems, sub-mm-wave ultra-wideband ultra-high-capacity communication links, and sub-mm-wave single-chip widely-tunable synthesizers for explosive detection spectroscopy,” according to Dr. John Albrecht, THz Electronics program manager for DARPA.

A transistor amplifier magnifies input signals to yield a significantly larger output signal. In 2007, Northrop Grumman set a new world record for transistor speed with an ultra-fast device to provide much higher frequency and bandwidth capabilities for future military communications, radar and intelligence applications.

The company produced and demonstrated an indium phosphide-based High Electron Mobility Transistor (InP HEMT) with a maximum frequency of operation of more than 1,000 gigahertz, or greater than one terahertz.

Source: EarthTimes.

“The interesting properties of graphene are all collective phenomena,” says Rotenberg, an ALS senior staff scientist responsible for the scientific program at ALS beamline 7, where the work was performed. “Graphene’s true electronic structure can’t be understood without understanding the many complex interactions of electrons with other particles.”

The electric charge carriers in graphene are negative electrons and positive holes, which in turn are affected by plasmons—density oscillations that move like sound waves through the “liquid” of all the electrons in the material. A plasmaron is a composite particle, a charge carrier coupled with a plasmon.

A theoretical model of plasmaron interactions in graphene, sheets of carbon one atom thick.

“Although plasmarons were proposed theoretically in the late 1960s, and indirect evidence of them has been found, our work is the first observation of their distinct energy bands in graphene, or indeed in any material,” Rotenberg says.

Understanding the relationships among these three kinds of particles—charge carriers, plasmons, and plasmarons—may hasten the day when graphene can be used for “plasmonics” to build ultrafast computers—perhaps even room-temperature quantum computers—plus a wide range of other tools and applications.

Strange graphene gets stranger

“Graphene has no band gap,” says Bostwick, a research scientist on beamline 7.0.1 and lead author of the study. “On the usual band-gap diagram of neutral graphene, the filled valence band and the empty conduction band are shown as two cones, which meet at their tips at a point called the Dirac crossing.”

Graphene is unique in that electrons near the Dirac crossing move as if they have no mass, traveling at a significant fraction of the speed of light. Plasmons couple directly to these elementary charges. Their frequencies may reach 100 trillion cycles per second (100 terahertz, 100 THz)—much higher than the frequency of conventional electronics in today’s computers, which typically operate at about a few billion cycles per second (a few gigahertz, GHz).

Plasmons can also be excited by photons, particles of light, from external sources. Photonics is the field that includes the control and use of light for information processing; plasmons can be directed through channels measured on the nanoscale (billionths of a meter), much smaller than in conventional photonic devices.

And since the density of graphene’s electric charge carriers can easily be influenced, it is straightforward to tune the electronic properties of graphene nanostructures. For these and other reasons, says Bostwick, “graphene is a promising candidate for much smaller, much faster devices—nanoscale plasmonic devices that merge electronics and photonics.”

The usual picture of graphene’s simple conical bands is not a complete description, however; instead it’s an idealized picture of “bare” electrons. Not only do electrons (and holes) continually interact with each other and other entities, the traditional band-gap picture fails to predict the newly discovered plasmarons revealed by Bostwick and his collaborators.

The team reports their findings and discuss the implications in “Observations of plasmarons in quasi-free-standing doped graphene,” by Aaron Bostwick, Florian Speck, Thomas Seyller, Karsten Horn, Marco Polini, Reza Asgari, Allan H. MacDonald, and Eli Rotenberg, in the 21 May 2010 issue of Science (“Observation of Plasmarons in Quasi-Freestanding Doped Graphene”).

Graphene is most familiar as the individual layers that make up graphite, the pencil-lead form of carbon; what makes graphite soft and a good lubricant is that the single-atom layers readily slide over one another, their atoms strongly bonded in the plane but weakly bonded between planes. Since the 1980s, graphene sheets have been rolled-up into carbon nanotubes or closed buckyball spheroids. Theorists long doubted that single graphene sheets could exist unless stacked or closed in on themselves.

Then in 2004 single graphene sheets were isolated, and graphene has since been used in many experiments. Graphene sheets suspended in vacuum don’t work for the kind of electronic studies that Bostwick and Rotenberg perform at ALS beamline 7.0.1. They use a technique known as angle-resolved photoemission spectroscopy (ARPES); for ARPES, the surface of the sample must be flat. Free-standing graphene is rarely flat; at best it resembles a crumpled bedsheet.

Using electrons to draw images of composite particles

“One of the best ways to grow a flat sheet of graphene is by heating a crystal of silicon carbide,” Rotenberg says, “and it happens that our German colleagues Thomas Seyller from the University of Erlangen and Karsten Horn from the Fritz Haber Institute in Berlin are experts at working with silicon carbide. As the silicon recedes from the surface it leaves a single carbon layer.”

Using flat graphene made this way, the researchers hoped to study graphene’s intrinsic properties by ARPES. First a beam of soft x-rays from the ALS frees electrons from the graphene (photoemission). Then by measuring the direction (angle) and speed of the emitted electrons, the experiment recovers their energy and momentum; the spectrum of the cumulative emitted electrons is transmitted directly onto a two-dimensional detector.
The result is an image of the electronic bands created by the electrons themselves. In the case of graphene, the picture is x shaped, a cross-sectional cut through the two conical bands.

The “bare electron” band-gap diagram of neutral graphene (right) shows the filled valence band and the empty conduction band forming two cones that meet at the Dirac crossing (arrow). But even low-resolution ARPES results (left) suggest that below the Dirac crossing, the energy and momentum distribution of charge carriers is not that simple.

“Even in our initial experiments with graphene, we suspected that the ARPES distribution was not quite as simple as the two-cone, bare-electron model suggested,” Rotenberg says. “At low resolution there appeared to be a kink in the bands at the Dirac crossing.” Because there really is no such thing as a bare electron, the researchers wondered if this fuzziness was caused by charge carriers emitting plasmons.

“But theorists thought we should see even stronger effects,” says Rotenberg, “and so we wondered if the substrate was influencing the physics. A single layer of carbon atoms resting on a silicon carbide substrate isn’t the same as free-standing graphene.”

The silicon-carbide substrate could in principle weaken the interactions between charges in the graphene (on most substrates the electronic properties of graphene are disturbed, and the plasmonic effects can’t be observed). Therefore the team introduced hydrogen atoms that bonded to the underlying silicon carbide, isolating the graphene layer from the substrate and reducing its influence. Now the graphene film was flat enough to study with ARPES but sufficiently isolated to reveal its intrinsic interactions.

The images obtained by ARPES actually reflect the dynamics of the holes left behind after photoemission of the electrons. The lifetime and mass of excited holes are strongly subject to scattering from other excitations such as phonons (vibrations of the atoms in the crystal lattice), or by creating new electron-hole pairs.

“In the case of graphene, the electron can leave behind either an ordinary hole or a hole bound to a plasmon—a plasmaron,” says Rotenberg.

Detailed ARPES results reveal that the energy bands of ordinary charge carriers (holes) meet at a single point, but conical bands of plasmarons meet at a second, lower Dirac crossing. Between these crossings lies a ring where the hole and plasmaron bands cross. The new band picture indicates how strongly plasmons couple to the charge carriers in graphene.

Taken together, the interactions dramatically influenced the ARPES spectrum. When the researchers deposited potassium atoms atop the layer of carbon atoms to add extra electrons to the graphene, a detailed ARPES picture of the Dirac crossing region emerged. It revealed that the energy bands of graphene cross at three places, not one.

Ordinary holes have two conical bands that meet at a single point, just as in the bare-electron, non-interacting picture. But another pair of conical bands, the plasmaron bands, meets at a second, lower Dirac crossing. Between these crossings lies a ring where the hole and plasmaron bands cross.

“By their nature, plasmons couple strongly to photons, which promises new ways for manipulating light in nanostructures, giving rise to the field of plasmonics,” Rotenberg says. “Now we know that plasmons couple strongly to the charge carriers in graphene, which suggests that graphene may have an important role to play in the merging fields of electronics, photonics, and plasmonics on the nanoscale.”

Source: NanoWerk.

The position is available immediately for a 9-month period, with the likely possibility of extension. Please send a cover letter with a brief summary of your research experience and interests, along with your CV, list of publications, and names and contact info of references to: bwilliam@ee.ucla.edu

Contact:
Prof. Benjamin Williams
Dept. of Electrical Engineering
68-117 Engineering IV
Box 951594
UCLA
Los Angeles, CA 90095-1594
http://www.ee.ucla.edu/~bwilliam/

Email: bwilliam@ee.ucla.edu

“Up until now, THz diode has only been available as a discrete device. The integration of a discrete THz diode into a circuit assembly with other active and passive components required wire bonding. Although this approach was not desired, it was unavoidable for many millimeter-wave applications due to the lack of a monolithic solution,” commented Jerry Curtis, Chief Executive Officer of GCS. “Our engineering team has overcome the technical challenges by developing a planar Schottky diode process with THz performance. This fully monolithic process, with MIM capacitor, spiral inductor, thin film resistor and backside via features, is now offered as a standard foundry process. The THz diode process has been demonstrated as a mixer in a W-Band up-converter with a conversion loss of 6 dB, with a LO frequency of 91.8GHz (12 dBm) and an IF of 2.25 GHz. The process is ideal for applications in mm-wave frequency transceivers, as well as Terahertz imaging systems,” continued Mr. Curtis.

Source: ChipDesign.

Applicants should have a background in condensed matter physics, optics, chemistry, electrical engineering, material science, or related fields. Experience in optical spectroscopies, ultrafast lasers, THz technology, or electro-optics device design is preferable, but not mandatory. In addition to technique development, the current main scientific interests of the group are exotic materials including superconductors and quantum magnets. Applicants should submit a CV, publication list, a very brief statement of research interests, and the names of three references as PDF attachments to npa@pha.jhu.edu. Please see http://www.pha.jhu.edu/~npa/ for further details.

Johns Hopkins University is an Affirmative Action/Equal Opportunity employers, and actively encourage applications from women and minority candidates.

Terahertz (THz) radiation is one of the hottest areas of modern physics research. This is because THz light waves, or T-rays as they are sometimes called, have great potential for spectroscopy and for the scanning of objects in a homeland security setting that are opaque to infrared and visible light.

The trouble is that THz light waves — which fall in the range of 0.3 to 10 trillion cycles per second or, equivalently, wavelengths of about 30 to 1000 microns — are difficult to make with traditional means. Now scientists at MIT have combined several technologies to obtain a versatile source of THz light.

They start with a quantum cascade laser (QCL) device, which differs fundamentally from a traditional semiconductor laser. In most traditional lasers, light comes from the recombination of an electron with a hole (a vacancy in the surrounding semiconducting material). But in a QCL device, light comes from the transition of an electron to a succession of ever lower energy levels in a series of layers in a sandwich-style structure of thin semiconducting layers.

This type of laser has a unique property: one electron (as it moves through the layers) triggers the release of many photons. The emitted light energy of the device can be changed by altering the thickness of the layers.

Population inversion is provided over a range of energies provided by the cascaded energy levels described above with the fine energy or wavelength selection provided by the laser cavity. In the MIT approach, tuning is achieved by changing the width of the laser light beam (and hence cavity) by precisely controlling the distance between a specially designed block material and the laser. This technique is analogous to changing the pitch of a guitar string by changing its diameter. In this case, the laser waveguide is much narrower than the wavelength of the light, hence the description of this setup as a “wire” laser.

Qi Qin of MIT says their cascade laser can be tuned continuously and controllably to produce terahertz radiation over a broad range. “At present, this is the only viable mechanism to achieve broad continuous tuning in terahertz quantum-cascade lasers,” says Qin.

Presentation CThU2, “Development of Tunable Terahertz Wire Lasers” by Qi Qin et al. is at 3 p.m. on Thursday, May 20.

Postgraduate Studentship – Open to all

PhD Project: Molecular beam epitaxy and terahertz quantum cascade lasers

We are seeking a PhD student in the field of experimental terahertz (THz) electronics. The post is available from 1 October 2010, and is an outstanding opportunity for an enthusiastic and dedicated person to join a world leading THz research team. The post is funded as part of recent major awards (totalling ~£6.5M) from both the UK Engineering and Physical Sciences Research Councils and the European Research Council.

You will use the technique of molecular beam epitaxy (MBE) to grow, atomic layer by atomic layer, a range of novel semiconductor based devices for THz emission, and characterise these structures both electrically and optically using the state-of-the-art facilities available within the School. One specific focus will be on the development of terahertz quantum cascade lasers, which were first demonstrated by a team led by supervisors Davies and Linfield. The University of Leeds now collaborates with many of the leading international researchers in the field of THz quantum cascade lasers, and there will be opportunities during the PhD to contribute to these programmes.

You will be able to make extensive use of our Terahertz Photonics Laboratory. Sited in the School of Electronic and Electrical Engineering, this Laboratory is a dedicated facility for the investigation and exploitation of THz frequency components and systems. Built in April 2004, it is probably the largest university facility for THz research in Europe/Asia, and one of the largest in the world. The facility contains eight optical bench systems, and includes: five pumped Ti:sapphire laser systems; a Bruker 66V FTIR spectroscopy system; three continuous flow helium cryostats, and one 1.2 K Oxford Instruments pumped helium bath cryostat, all with optical access; a 12 T, 8 mK base temperature dilution refrigerator; purged and evacuated THz time-domain spectroscopy systems, including an ultra-broad bandwidth capability; and on-chip, guided-wave THz apparatus. You will also make use of our III-V semiconductor MBE laboratory, nanotechnology cleanroom, and microwave electronics laboratories.

Supervisors: Professor Edmund Linfield and Professor Giles Davies.

Value: Full fees and maintenance at the standard EPSRC rate is available. This is a European Research Case award with a duration of 3 years.

Entry Requirements: An upper second class honours, or an MSc, in Physics, Electronic Engineering, Nanoscale Science & Technology, or a related discipline.

Application deadline: 01 June 2010

Further information: To discuss this project further informally, please contact Professor Edmund Linfield.

How to apply: Formal applications for research degree study should be made either on line through the University website, or on the University’s application form. Please return the completed application form to the Research Degrees & Scholarships Office, University of Leeds, LS2 9JT, or e-mail a scanned application to phd@engineering.leeds.ac.uk

Please provide all the documents required as soon as possible, either included with your paper application or sent directly to the Graduate School Office if you apply online. Scanned copies are acceptable for a conditional offer; however you will need to provide originals or certified copies at registration. These will include your degree certificate(s), transcripts of marks achieved in previous degrees, plus evidence of English language qualifications if your first language is not English and you do not hold a degree from an English-speaking country. Please note, if you intend to send academic references we can only accept them if they are on official letter headed paper and contain an original signature and stamp; they must arrive in sealed envelopes. Alternatively, the Faculty will contact your named academic referees directly.

If you have any questions please contact our Graduate School Office.
e: phd@engineering.leeds.ac.uk
t: +44 (0)113 343 8000

Led by BU’s Richard Averitt, the team has developed a new way to detect and control terahertz (THz) radiation using optics and materials science. This type of radiation is made up of electromagnetic waves that can pass through materials safely. Their work may pave the way for safer medical and security scanners, new communication devices, and more sensitive chemical detectors.

Scientists and engineers have long sought devices that could control THz transmissions. Such a device would be a technological breakthrough because it would allow information to be sent via THz waves. Like X-rays, these waves can pass through solid materials, potentially revealing hidden details within. Unlike the ionizing energy of real X-rays, THz radiation causes no damage to materials as it passes through them.

The quest to create devices that emit or manipulate THz radiation is often referred to as a race to fill in the “THz gap,” since the frequency of THz radiation on the electromagnetic spectrum falls in between microwave and infrared radiation — both of which are already broadly used in communication.

This race has often stumbled right out of the blocks, however, because no technologies have proven able to effectively solve the basic problem of manipulating the properties of a beam of THz radiation. Now Averitt and his colleagues have made an important step in this direction by using an unusual class of new materials known as “metamaterials.”

Metamaterials are unusual in the way they interact with light, giving them properties that don’t exist in natural materials. They have grabbed headlines and captured the popular imagination in recent years after several groups of researchers have used metamaterials to achieve limited forms of “cloaking” — the ability of a material to completely bend light around itself so as to appear invisible.

Averitt uses these same sorts of metamaterials to interact with and change the intensity of a beam of THz radiation. His device consists of an array of split-ring-resonators — a checkerboard of flexible metamaterial panels that can bend and tilt. By rotating the panels, his team can control the electromagnetic properties of a beam of THz energy passing by them.

“The idea is that you can manipulate your terahertz beam by reorienting the metamaterial elements as opposed to reorienting your beam,” says Averitt.

Arrays of these metamaterial panels could potentially function as pixels on a camera that detects THz radiation, he says. Absorption of THz radiation would cause the panels to tilt more or less depending on the intensity of the THz bombarding them.

“One of the goals, from a technological point of view, is to be able to do stand-off imaging, to be able to detect things beneath a person’s clothes or in a package,” says Averitt.

Such detection applications, though, would require more powerful THz sources like quantum cascade lasers, which are under development — though great technological strides have been made in the last few years.

Presentation CtuF3, “Structurally Reconfigurable Metamaterials at Terahertz Frequencies,” by Hu Tao and Richard D. Averitt takes place Tuesday, May 18 at 8:30 a.m.

Source: EarthTimes.

Chalmers University of Technology, Department of Microtechnology and Nanoscience (MC2) is announcing one PhD student position in a European project on THz devices. This position can also be started with a diploma work.

Microwave Electronics Laboratory at MC2 is one of the most research-intense laboratories at Chalmers with an international reputation in low-noise, high power, and circuit design for frequencies ranging from few and up to several hundred GHz. Alongside our traditional research on high-speed low-noise transistors, we are exploring novel exciting high-frequency devices for THz region (1000 GHz) in the framework of a joint European project together with Spain, France, and Great Britain. The research involves device design, semiconductor processing, advanced electrical characterization, and modeling. The results will be reported in scientific journals and at international conferences.

THz technology fills up the final frontier between electronics and photonics with new applications in sensors and high-speed communication. It is however extremely difficult to design THz devices with sufficient gain and several approaches are pursued worldwide.

Job descriptionA PhD education in this field gives you competence in a new field, an international network and contributes to new essential knowledge and innovation. After the Ph.D, you are in an excellent position to go further into academia or industry.

Required qualifications

Suitable background is a M.Sc in Engineering Physics (F) or Electrical Engineering. We are strongly encouraging women to apply for this position.Application procedure

The application shall be written in English and include the following items:

1. An application of a maximum of one A4 page containing your specific qualifications for the position
2. Attested copies of education certificates, including grade reports and other documents
3. Curriculum Vitae
4. Letters of recommendation and name of reference persons (optional)

The application shall be sent electronically as pdf or zipped documents. Please use the link at the top of the page to reach the application form.

If any material is not available electronically or cannot be transferred to pdf format, the material can be sent as a hard copy to Registrar. The applicants name and the reference number (REF 2010/97) must be written on the first page of the application.

Address:
Registrar
Chalmers University of Technology
SE-412 96 Göteborg
Sweden

Further information

Professor Jan Grahn
031-772 1055
jan.grahn@chalmers.se

The mobile scanner works on a test wall. A software system reveals the structure of the concealed paintings. Credit: Fraunhofer IWS

Many church paintings are hidden from sight because they were painted over centuries ago. In the 16th century, for instance, Reformation iconoclasts sought to obscure the religious murals, while in later times the iconoclast images often were painted over once again. Several layers of paintings from various epochs can now be found superimposed on top of each other. If mechanical methods are used to uncover these pictures there is always a risk that the original work will be damaged.

What’s more, the more recent layers and pictures on top of the original, which are also worthy of preservation, would be destroyed. Research scientists at the Fraunhofer Institute for Material and Beam Technology IWS in Dresden are now working on a non-destructive method for rendering these works visible, which involves the use of terahertz (THz) radiation. In the TERAART project funded by the German federal ministry of education and research (BMBF) they are cooperating with Dresden University of Technology, the FIDA Institute for Historic Preservation in Potsdam and the Dresden Academy of Fine Arts.

“We use THz radiation because it can penetrate the plaster and lime wash even if the layer is relatively thick. Unlike UV radiation for example, THz radiation does not damage the work of art. Infrared beams cannot be considered because they do not penetrate deep enough. Microwaves offer no alternative either, because they do not achieve the necessary width and depth resolution,” explains Dr. Michael Panzner, scientist at the IWS. A mobile system that can be used anywhere was developed to conduct the examinations. It consists of a scanner with two measuring heads which travels contactlessly over the wall. One measuring head transmits the radiation, the other picks up the reflected beams. The researchers were supported by the Fraunhofer Institute for Physical Measurement Techniques IPM, which built the adapted THz component.

“To produce the THz radiation we use a femtosecond laser incorporating the design principle of a fiber laser. The THz time domain spectroscopy technique applied by us utilizes the short electromagnetic pulses with a duration of just one to two picoseconds produced by the femtosecond laser. Each layer and each pigment reflects these pulses differently so that both a picture contrast as well as depth information can be obtained,” says Panzner. “The measured results provide information for example about the thickness of the layers, what pigments were used and how the colors are arranged. A specially developed software system puts the measured results together to form a picture displaying the structure of the concealed paintings.”

On a test wall, on which paintings in various types of paint were painted over with distemper, the scientists have already succeeded in revealing the structures of the concealed pictures. The next step will be to conduct a practical test in a church. The experts are also confident of being able to use THz radiation to detect the presence of carcinogenic biocides on and in works of art made of wood or textiles. “Preservationists will be very interested in our reveal-all-scanner for works of art,” affirms Panzner.

Source: PhysOrg.com.

Toptica is a global market leader for THz sources and their applications, offering laser-based time and frequency domain sources. Part of Toptica’s portfolio is offering customers a THz Standard Package plus Spectroscopy Kit product which uses a coherent detection technique for continuous wave (“cw”) THz signals. Under the terms of the Licensing Agreement, T-Ray will collect royalties on the sales of this product in the United States.

“The quality of Toptica’s products and their expertise in the field of THz imaging are world class,” said Thomas Braun, CEO of T-Ray. “This is a significant endorsement of T-Ray’s cw THz platform technology. While T-Ray continues to focus on developing its own skin cancer imaging device, we are forecasting additional Licensing Agreements to be concluded this year, positioning the Company for accelerated growth.”

T-Ray’s platform THz imaging technology has been shown to have numerous potential applications including homeland security, the detection of explosives and ceramic knives; process control in the paper, plastics, petro chemical and pharmaceutical industries; and medical imaging for detection of skin and other cancers. THz waves are also a safe, accurate, and economical alternative to other scanning methods such as high frequency ultrasound, magnetic resonance imaging, and near-infrared imaging. This emergent technology has the potential to revolutionize the way many diseases are diagnosed, and ultimately cured. Numerous studies have shown that THz imaging can be used to image various cancers which continues to be the focus of T-Ray’s skin cancer imaging research and development.

One of the main sources of THz radiation, the interdigitated photoconductive antenna, can now be ‘tuned’ to THz frequencies that were previously difficult to reach. Researchers at the Ecole Normale Supérieure in France found that changing the spacing between the electrodes in the antenna’s structure enables the emission spectrum to be centred at a chosen frequency; a property that will be useful for spectroscopy and imaging, where access to particular parts of the THz spectrum is needed.

The generation gap

There are many possible applications in the THz range (0.1-10 THz) including explosives and drugs detection, medical imaging, gas detection, high-speed communications and fundamental studies of the physics of materials or very low energy systems (1 THz~4 meV). However, despite intense research efforts, there have been many challenges that have not yet been overcome in achieving a miniature, efficient THz source. Today’s research is mainly focused on a variety of different compact optoelectronic devices like photoconductive antennas (PCAs) which operate at room temperature but need an external laser excitation, or THz quantum cascade lasers which are powerful but currently operate at cryogenic temperatures. PCAs have been used and studied as a source of THz radiation for over 20 years. One of the most efficient is the interdigitated PCA with its electrode comb geometry which radiates in the THz range when illuminated with, typically, an infrared femtosecond pulsed laser. They are now increasingly being used in laboratory applications as they radiate with broadband emission and high power; they suffer little from diffraction effects as the illuminated surface area is large; and they operate at low electrical input power.

A selective response

The team at Ecole Normale Supérieure have been developing and using interdigitated PCAs as a pulsed source for studies with a THz time-domain (TDS) setup which is used to probe physical or chemical properties related to low energy interactions within materials or compounds. They have been studying the geometry of interdigitated PCAs in order to understand their mechanisms better and therefore create more efficient THz sources. In their most recent investigation, they found that the emitted spectral peak frequency increased from 0.73 to 1.33 THz as the spacing between the electrodes in the structures was decreased from 20 to 2 ?m. This result enables the frequency response of an interdigitated PCA to be selected by the design of its electrode spacing geometry. A big challenge that the team faced to achieve this result was the fabrication of the devices with the electrode spacing on the micron level as the standard UV contact lithography technique starts to reach its limits. They overcame this by optimising the processing procedure and the team next plan to develop interdigitated PCAs to cover the high frequency part of the THz range using the same laser source. “This could be achieved by further reducing the electrode spacing of the interdigitated structure but it will need a different lithography technique,” said Julien Madéo, a researcher at Ecole Normale Supérieure. “We are also investigating new interdigitated geometries with different patterns to achieve higher frequency emission.”

Future improvements

With worldwide research efforts underway to achieve more efficient THz sources, the team predict that the use of PCAs as THz sources will rapidly progress as a better understanding is developed from experiments and simulations. “We believe that electromagnetic simulations of these devices will continue to be important and allow the antenna geometry to be adapted to the required spectral range,” said Madéo. “Another challenge though is that these structures exhibit a weak efficiency (< 1%), and high power and expensive pulsed lasers are needed to produce relatively strong THz electric fields. We will need to think about new geometries and new materials to improve these issues, possibly combined with the use of cheaper and compact fibre-based laser systems. Improving these types of sources will permit the THz technological range to become mature and comparable to those used in microwave electronics and infrared optical systems.”

The Letter presenting the results on which this article is based can be found on the IET Digital Library.
For further reading, please visit www.lpa.ens.fr
Source: IET.

The article examined experimental results from a video-rate device. The device uses terahertz (THz) rays that emit a continuous narrow bandwidth radiation of 0.1 (THz). The instrument creates a two-dimensional image of a point in an object. The image is reconstructed at a rate of 16 milliseconds per frame with a four-element detector array. The number of detectors, the configuration of the detection array and how well the baselines are calibrated affects the image resolution and quality.

“Scientists favor terahertz radiation because it can transmit through most non-metallic and non-polar mediums,” said Federici. “When a terahertz system is used correctly, people can see through concealing barriers such as packaging, corrugated cardboard, walls, clothing, shoes, book bags, pill coatings, etc. in order to probe for concealed or falsified materials.”

Once the rays penetrate those materials, they can also characterize what might be hidden – be they explosives, chemical agents or more – based on a spectral fingerprint the rays will sense which can identify the material. terahertz radiation also poses minimal or no health risk to either the person being scanned or the THz system operator.

At this time, instruments using terahertz imaging are widely used in laboratories and have shown some limited use in commercial applications. However, a THz imaging system for security screening of people has not yet reached the market. Researchers say that such a system is at least five years away. The NJIT device, however, has great promise. According to Federici, THz imaging systems have an inherent advantage over millimeter wave imaging systems due to the intrinsically improved spatial resolution that one can achieve with the shorter wavelength THz systems (typically 300 micrometer wavelength) compared to longer wavelength millimeter wave systems. However, video-rate THz imaging systems are not as well advanced as their millimeter wave counterparts.

One technical limitation in developing video-rate THz imaging is the cost of THz hardware components including detectors. Consequently, THz imaging systems create images using a very small number of detectors in contrast to the million or more detectors that are used in digital cameras. According to Federici, one can use advanced imaging techniques, such as synthetic aperture imaging methods, to compensate for the relatively few number of THz detectors in an imaging system.

“The idea has been to apply different methods of imaging with radio waves, where many of the ideas for synthetic aperture imaging originated, to terahertz rays,” said Federici. His research team has focused in particular on applications of synthetic aperture imaging to the terahertz range. “The advantage of this particular method is the ability to generate terahertz images with a large number of pixels using a limited number of terahertz detectors. This imaging method should also be capable of video-rate imaging, thereby enabling the real-time monitoring of people hiding concealed explosives or other dangers.” A typical imaging system would be analogous to a still or video camera designed for this purpose.

In 2005, Federici and his research team received a U.S. patent for a terahertz imaging system and method that enables video-rate THz imaging with a limited number of detectors. Since 1995, terahertz imaging has grown in importance as new and sophisticated devices and equipment have empowered scientists to understand its potential. The U.S. Department of Homeland Security, the Army Research Office, Department of Defense, and the National Science Foundation support Federici’s work.

While researchers have focused on the potential applications of terahertz rays for directly detecting and imaging concealed weapons and explosives, they say another application is the remote detection of chemical and biological agents in the atmosphere.

Source:
New Jersey Institute of Technology
and MedicalNewsToday.

Contributions addressing subjects pertaining, but not limited to, the following are solicited: applications of terahertz and IR spectrometry techniques in pharmaceutical, analytical, polymer, biological, and other areas. Topics may also include other spectroscopic techniques in solving important problems.

The 41st Middle Atlantic Regional meeting (MARM 2010) will be hosted by the ACS Delaware Section and held on April 10-13, at the historic Hotel du Pont, in Wilmington, DE. MARM 2010 is cosponsored by several ACS regional sections including the Southeastern Pennsylvania section of the American Chemical Society (SEPSACS).

The deadline for abstracts is February 15, 2010. Abstracts should be submitted online at the following link (login required): http://abstracts.acs.org/chem/marm_2010
under “Analytical Chemistry: We invite you to present on Advances in IR & Terahertz…”

Please do not hesitate to contact the conference organizers for any questions:

Dr. Martha Hollomon, General Chair: marthahollomon@comcast.net
Dr. Allen Denio, Exhibits Chair: alvaldenio@aol.com
Dr. Anis Rahman, Session Chair: a.rahman@arphotonics.net