Terahertz Technology

Abstract: Emitter injection in terahertz quantum cascade lasers: Simulation of an open system

2012-03-06T10:44:00.000-08:00

http://apl.aip.org/resource/1/applab/v100/i10/p102102_s1?isAuthorized=no

F. Wang, X. G. Guo, H. Li, and J. C. Cao

Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China

We investigate the carrier transport properties of a three-well terahertz quantum cascade laser which is considered as an open system by using self-consistent Bloch-Poisson equations. The simulation results show that a dynamic equilibrium is achieved, and the electric potential of each period slightly changes with time. Compared to other simulation methods with the cyclic boundary condition approximation, our open system modeling gives more reliable results on the current density-applied electric field and population inversion-applied electric field characteristics. Our modeling method can give more realistic results of working terahertz quantum cascade lasers without increasing the simulation complexity.

37th International Conference on Infrared, Milimeter, and Terahertz Waves (IRMMW-THz)

2012-03-05T19:49:00.000-08:00

The 37th International Conference on Infrared, Milimeter, and Terahertz Waves (IRMMW-THz) will be held in Wollongong, Australia.
The IRMMW-THz conference, begun in 1974, is the oldest and largest continuous forum specifically devoted to the field of ultra-high-frequency electronics and applications. The scope of the conference extends from millimeter wave devices, components and systems to far-infrared detectors and instruments. It encompasses micro- and nano-scale structures to large accelerators and tokomaks and applications as diverse as space science, biology and medicine.

Conference Chairs

R. A. Lewis, University of Wollongong, Australia, roger@uow.edu.au
C. Zhang, University of Wollongong, Australia, czhang@uow.edu.au

Local Organizing Committee

C. A. Freeth (School of Physics, University of Wollongong)
J. Horvat (School of Physics, University of Wollongong)
A. V. Pan (ISEM, University of Wollongong)
R. Vickers (School of Physics, University of Wollongong)
X. L. Wang (ISEM, University of Wollongong)

National Committee

D. Abbott, School of EEE, The University of Adelaide
A. Argyros, Sydney University
S. X. Dou, University of Wollongong
J. Du, CSIRO
Min Gu, E. Swinburne University of Technology
A. Hellicar, CSIRO
A. Lee, Macquarie University
H. Pask, Macquarie University,
A. Rosenfeld, University of Wollongong
V. Wallace, University of Western Australia

Plenary Speakers

Kwo Ray Chu	National Taiwan University, Taiwan
Ben Eggleton	University of Sydney, Australia
Kaori Fukunaga	National institute of Information and Communications Technology, Japan
Alexey Kuzmenko	University of Geneva Switzerland
Gennadii Nikolaevich Kulipanov	Novosibirsk High Power Free Electron Laser (NovoFEL)
Gregory S. Nusinovich	University of Maryland, USA
Xuechu Shen	Shanghai Institute of Technical Physics, China
Koichiro Tanaka	Kyoto University, Japan

for more information click here

Picometrix hand-held Terahertz imaging -In-space NDI Technology workshop

2012-03-05T15:28:00.000-08:00

http://www.nasa.gov/pdf/626494main_3-3-A_Zimdars.pdf

Terahertz emission from a two-color plasma filament in a slot waveguide

2012-03-05T10:14:00.000-08:00

http://apl.aip.org/resource/1/applab/v100/i9/p091113_s1?bypassSSO=1

Terahertz emission in forward direction from a long two-color filament placed in the center of a slot waveguide is reported. The waveguide improves the collection and imaging of the generated THz radiation. By tuning the plate separation and position of the waveguide along the filament axis, the emitted mode can be matched to the collection optics. We achieved an increase of the detected electric field by 40% and of the THz pulse energy by four times compared to the case without waveguide.

Quantum-dot laser produces multiple wavelengths for terahertz generation

2012-03-05T08:16:00.001-08:00

http://www.laserfocusworld.com/articles/print/volume-48/issue-03/newsbreaks/quantum-dot-laser-produces-multiple-wavelengths-for-terahertz-generation.html

03/05/2012

By John Wallace
Senior Editor

A single quantum-dot (QD) laser diode developed by a group at the University of Dundee (Dundee, Scotland) generates stable dual and/or multiple longitudinal modes in the near-infrared. The device has potential for production of terahertz radiation via optical difference-frequency generation.

Temperature-stabilized at 20°C, the laser diode is situated in an external-cavity setup containing two volume Bragg gratings (VBGs): one that selectively returns 1177 ±0.5 nm and 1182 ±0.5 nm wavelengths, and the other that selectively returns 1257 ±0.5 nm and 1262 ±0.5 nm wavelengths. The glass VBGs have an efficiency of about 15% and grating tilts of 1° to prevent backreflections. The difference frequencies for the two gratings are 0.946 ±0.019 THz and 1.078 ±0.021 THz, respectively.

When driven at a current of 70 mA, the laser emitted from the ground state (GS; matching VBG2); at 210 mA, excited-state (ES; matching VBG1) emission dominated the output. Intermediate currents produced a mix of GS and ES emission. Because each VBG is multiplexed (containing two gratings), a total of four wavelengths can be produced by the laser, with the relative output of each of two pairs adjustable by varying the current (the figure shows the output for a 150 mA current). In addition to photomixing for terahertz generation (and potentially two-color terahertz imaging), the laser is useful for spectroscopy. Contact Ross Leyman at r.r.leyman@dundee.ac.uk.

Focus on Terahertz in India, the Indian Institute of Technology, and S.K. Ray

2012-03-02T12:13:00.003-08:00

http://www.iitkgp.ac.in/fac-profiles/showprofile.php?empcode=aSddY
My Note: I was searching for Terahertz research in India, and came across this page (which I have abbreviated), I intend to dig deeper on the topic of THz in India and China. If you would like your website, company or research mentioned please email me.

Samit Kumar Ray

	S K Ray Ph.D.(IIT Kharagpur) Professor, Physics & Meteorology Head of the Department, Physics & Meteorology
	S K Ray joined the Institute in 1991

Contact Addresses

Residence	A-130, IIT Campus, Kharagpur 721302
Phone (office)	+91 - 3222 - 283838
Phone (residence)	+91 - 3222 - 283839 (IIT Phone)
email	physkr @ phy.iitkgp.ernet.in
More Information	http://www.facweb.iitkgp.ernet.in/~samit/index.htm

Research Areas

Semicondutor nanostructures
Condensed Matter Physics
Thin Films
Photovoltaics

Awards & Honours

BOYSCAST Fellow Award (1995)
Homi J.Bhabha Award for Research in Applied Sciences from the University Grant Commission (2002)
INSA Young Scientist Award (1993)
Materials Research Society of India (MRSI) Medal (2007)
CDIL Award for Industry of IETE (1997)
INSA Young Scientist (1993)
Homi J. Bhabha award (2001)
MRSI Medal (2007)
CDIL Award, IETE (1997)

Current Sponsored Projects

Project Title : MBE growth of strained Si/Ge layers and self-assembled Ge islands for heterostructure MOSFETs and flash memory devices
Principal Investigator : S. K. Ray
Sponsor : DST, New Delhi
Project Title : Development & characterization of nanostructured thin films for SiGe quantum well infrared photodetector and ferroelectric based gas/chemical sensors
Principal Investigator : S. K. Ray
Co-Principal-Investigators : I. Manna & A. Dhar
Sponsor : DRDO
Project Title : Fabrication and characterization of Novel Photonic Crystal Structures and Si/Ge Quantum Dots for Photonic Applications
Principal Investigator : S. K. Ray
Co-Principal-Investigators : L. Pavesi
Sponsor : India-Trento Programme for Advanced Research
Project Title : Terahertz emission of Si/SiGe structures doped with shallow acceptors
Principal Investigator : S. K. Ray
Co-Principal-Investigators : P. Roychoudhuri
Sponsor : DST-RFBR
Project Title : Fabrication of group-IV semiconductor (Si&Ge) nanowires for flash memory and nanoelctronic devices
Principal Investigator : Prof. S. K. Ray
Co-Principal-Investigators : Prof. S. Maikap, CGU, Taiwan
Sponsor : India-Taiwan Programme in Science & Technology

On-going Consultancy Projects

Project Name : Thin Film Characterization
Client : Various department s& agaencies
Consultant : S. K. Ray
Co-consultant(s) : A. Dhar

Publications: 2010 - 2011

Room temperature infrared photoresponse of self assembled Ge/Si (001) quantum dots grown by molecular beam epitaxy by 1. R. K. Singha, S. Manna, S. Das, A. Dhar, and S. K. Ray Applied Physics Letters, 96, 233113 (2010)
Microstructural characteristics and phonon structures in luminescence from surface oxidized Ge nanocrystals embedded in HfO2 matrix by S. Das, R. K. Singha, S. Gangopadhyay, A. Dhar, and S. K. Ray, J. of Applied Physics, 108, 053510 (2010)
Photoinduced charge transfer and photovoltaic energy conversion in self-assembled N,N-dioctyl-3,4,9,10-perylenedicarboximide nanoribbons by S. Karak, S. K. Ray, and A. Dhar Applied Physics Letts, 97, 043306 (2010)
Light emission and floating gate memory characteristics of germanium nanocrystals by S. Das, S. Manna, R.K.Singha, A.leksei Anopchenko, N. Daldosso, L. Pavesi, A. Dhar, and S. K. Ray, â€œ Phys. Status Solidi A, DOI 10.1002/pssa.201 (2010)
Nonvolatile and unipolar resistive switching characteristics of pulsed laser ablated NiO films by D. Panda, A. Dhar, and S. K. Ray J. Appl. Phys., 108, 104513, (201)
Temperature dependent growth and optical properties of SnO2 nanowires and nanobelts by S. P. Mondal, S. K. Ray, J Ravichandran and I. Mannaâ€œ Bull. Mater. Sci, 33, , p. 357 (2010)
Microstructural, chemical bonding, stress development and charge storage characteristics of Ge nanocrystals embedded in hafnium oxide by S. Das, R. K. Singha, S. Manna, S. Gangopadhyay, A. Dhar, S. K. Ray J. Nanopart. Res., 13, p. 587 (2011)
Improvement of efficiency in solar cells based on vertically grown copper phthalocyanine nanorods by S Karak, S K Ray and A Dhar J. Phys. D: Appl. Phys, 43, p. 245101 (2010)
Interplay of defects in 1.2 MeV Ar irradiated ZnO by S. Chattopadhyay, S. Dutta, D. Jana, S. Chattopadhyay, A. Sarkar, P. Kumar, D. Kanjilal, D. K. Mishra, and S. K. Ray Journal of Applied Physics, 107, p.113516 (2010)
Structural and optical properties of germanium nanostructures on Si(100) and embedded in high-k oxides by Samit K Ray, Samaresh Das, Raj K Singha, Santanu Manna, Achintya Dhar, â€œ Nanoscale Research Letters, 6, 224 (2011)
Optical property modification of ZnO: Effect of 1.2 MeV Ar irradiation by Soubhik Chattopadhyay, Sreetama Dutta, Palash Pandit, D. Jana, S. Chattopadhyay, A. Sarkar,P. Kumar, D. Kanjilal, D. K. Mishra, and S. K. Ray, Phys. Status Solidi C, 8, p.512 (2011)
Structural and impedance spectroscopy of pseudo-co-ablated (SrBi2Ta2O9)(1âˆ’x)â€“(La0.67Sr0.33MnO3)x Composites by S Maity, D Bhattacharya and S K Ray J. Phys. D: Appl. Phys., 44, p.095403 (2011)
Influence of deposition temperature on structure and morphology of nanostructured SnO2 films synthesized by pulsed laser deposition by S .K. Sinha, R. Bhattacharya, S.K. Ray, I. Manna Mterials Letters, 65, pp. 146-149, (2011)

Publications: 2009 - 2010

Enhanced broadband photoresponse of Ge/CdS nanowire radial Heterostructures by S. P. Mondal and S. K. Ray Applied Physics Letters, 94, 223119 (2009)
Ge based nanostructures for electronic and photonic devices by S.K. Ray, R.K. Singha, S. Das, S. Manna, A. Dhar, Microelectronics & Reliability, doi:10.1016/j.micror (2010)
Photoluminescence and electrical transport characteristics of ZnO nanorods grown by vapor-solid technique by S. Mandal, K. Sambasivarao, A. Dhar, and S. K. Ray Journal of Applied Phys, 106, 024103, (2009)
Amperometric Detection of Glucose Biomolecules Using ZnO Tripods and Nanorods: A Comparative Study by 10. Surajit Mandal, Kurra Sambasivarao, Himadri Mullick, Achintya Dhar, Tapan Kumar Maiti, and Samit Kumar Ray Sensors Letters, Vol. 7, 1â€“5 (2009)
Investigation of strain in self-assembled multilayer InAs/GaAs quantum dot heterostructures by S. Adhikary, N. Halder, S. Chakrabarti, S. Majumdar, S.K. Ray, M. Herrera, M. Bonds, N.D. Browningâ€œ Journal of Crystal Growth, 312, pp. 724-729 (2010)
Single Hole Charging at Room Temperature of Ge Quantum Dots Grown on Si(001) by Molecular Beam Epitaxy by R. K. Singha, S. Das, A. Dhar, S. K. Lahiri, S. K. Ray, A. Surawijaya, and S. Oda Nanoscience and Nanotechnology Letters, 1, pp. 82-86 (2009)
Improved charge storage characteristics of the tetralayer non-volatile memory structure using nickel nanocrystal trapping layer by D. Panda, A. Dhar and S. K Ray Semicond. Sci. Technol. 24, 24, 115020 (2009)
Dielectric and transport properties of carbon nanotube-CdS nanostructures embedded in polyvinyl alcohol matrix by S. P. Mondal, R. Aluguri, and S. K. Ray Journal of Applied Physics, 105, 114317 (2009)
Structural and Magnetic field dependent transport properties of p-MnxGe1-x/n-Ge heterojunction by S. Majumdar, A. K. Das and S. K. Ray International Journal of Modern Physics B, 23, 3579 (2009)
Deep-level spectroscopy studies of confinement levels in SiGe quantum wells by I.V. Antonova, E. P. Neustroev, S.A. Smagulova, M.S. Kagan, P.S.Alekseev, S.K. Ray, N.Sustersic, and J. Kolodzey, â€œ Journal of Applied Physics, 106, 084903 (2009)
Confinement levels in SiGe quantum wells studied by charge spectroscopy by M. Kagan, I. Antonova, E. Neustroev, S. Smagulova, P. Alekseev, S. K. Ray, N. Sustersic, and J. Kolodzey Phys. Status Solidi ,C, 6, p.270 (2009)
Confinement Levels in Passivated SiGe/Si Quantum Well Structures by I.V. Antonova, E.P. Neustroev, S.A. Smagulova, M.S. Kagan, P.S. Alekseev, S.K. Ray, N. Sustersic and J. Kolodzey Solid State Phenomena, 156-158, p.541 (2010)
Organic photovoltaic devices based on pentacene/N,N0-dioctyl-3,4,9,10-perylenedicarboximide heterojunctions by S. Karak, V.S. Reddy, S.K. Ray, A. Dhar Organic Electronics, 10, pp. 1006â€“1010 (2009)
Photovoltaic properties of pentacene/[6,6]-phenyl C61 butyric acid methyl ester based bilayer hetero-junction solar cells by V S Reddy, S Karak, S K Ray and A Dhar J. Phys. D: Applied Physics, 42, 145103 (2009)
Microstructure and magnetic properties of melt-spun Cu0.95Co0.05 granular alloy by S. Majumdar, R.K.Singha, J.Yoon, M.H.Jung, M.Chakraborty, A.K.Das, S.K.Ray PhysicaB, 404, p. 1858 (2009)
Phase composition and electrical characteristics of nickel silicide Schottky contacts formed on 4Hâ€“SiC by I Nikitina, K Vassilevski, A Horsfall, N Wright, A G Oâ€™Neill, S K Ray, K Zekentes and C M Johnson Semiconductor Science & Technology, 24, 055006 (2009)
Improved photovoltaic properties of pentacene/N,N0-Dioctyl-3,4,9,10-perylenedicarboximide-based organic heterojunctions with thermal annealing by S. Karak, S.K. Ray, A. Dhar Solar Energy Materials & Solar Cells, 94, pp. 836â€“841 (2010)
Bonding, vibrational and electrical characteristics of CdS nanostructures embedded in polyvinyl alcohol matrix, by S. P. Mondal, A. Chakraborty, A. Dhar and S. K. Ray Journal of Applied Physics, 105, 084309 (2009)
Properties of self-assembled Ge Islands grown by molecular beam epitaxy by S. K. Ray, R. K. Singha, S. Das, K. Das and A. Dhar International Journal of Nanotechnology, Vol. 6, pp.552-566 (2009)

National Science Foundation awards Mikhail Belkin NSF Career Award for work in THz

2012-03-02T07:48:00.002-08:00

http://www.eurekalert.org/pub_releases/2012-03/uota-uef030212.php
Mikhail Belkin, assistant professor in the Department of Electrical and Computer Engineering, was awarded for his work on "Terahertz Semiconductor Laser Sources for Operation Above Cryogenic Temperatures." The objective of his research is to investigate and develop widely and continuously tunable terahertz quantum-cascade lasers and other active devices based upon monolithic and voltage tunable metamaterial waveguides. The demonstration of amplifier and distributed feedback configurations will allow the output power to be scaled to several milliwatts or greater with a directive beam pattern. The broader impacts of his research lie in the development of a new approach for achieving tunable semiconductor lasers. Additionally, terahertz technology requires improved sources and detectors for sensing, imaging and spectroscopy.

Fraunhofer unveils new time-domain THz system for commercial use

2012-03-02T07:06:00.000-08:00

Touchless and Non-destructive – Fiber optic terahertz screens materials and analyses substances

http://www.hhi.fraunhofer.de/en/project-of-the-month/fiber-optic-terahertz-screens-materials-and-analyses-substances/

Fraunhofer HHI has developed a complete system for the mobile, flexible and low-cost practical use of terahertz radiation in industrial environments. This complete system is based on a chip developed by Fraunhofer HHI in combination with components and technologies originally developed for fiber optic telecommunications.

THz combines the characteristics of radio waves and infrared light

Terahertz, or THz for short, is a frequency band which until only recently was very difficult to exploit. In the electromagnetic spectrum THz is precisely situated between radio waves and infrared light and combines the characteristics of these two frequencies. This particular combination means that the radiation – which is completely safe for humans – can penetrate and analyze materials and substances, thus opening up a new range of possibilities.

Mobile and affordable – terahertz as a complete system

Terahertz sensor systems are at a premium when it comes to non-destructive investigation of the insides of materials. Only terahertz systems used to be heavy, cumbersome and complex, and a great deal of serious development went into terahertz technologies before the apparent good qualities of terahertz could be harnessed for practical uses in industrial environments at acceptable costs. With its "TeraWave Time Domain Spectrometer" complete system Fraunhofer HHI has now found a way with a system that integrates all the components and processes required for its mobile, flexible real-world usage.

Developed by Fraunhofer HHI, the "TeraWave Time Domain Spectrometer" complete system packs all the components and processes needed (Photo: Fraunhofer HHI)

A new chip from Fraunhofer HHI tones up THz for real-world usage

The control unit of the complete systems contains telecom-developed lasers which emit ultra-short light pulses on what is known as the "Telecom wavelength" of 1.5 µm. This laser light is sent via flexible standard fiber optic cable to moveable THz emitter and detector heads. What is really crucial here are the Opto-Chips built into these THz heads.

Fraunhofer HHI THz sensor systems can be flexibly integrated into fabrication workflows

For realization of the complete system, Dr. Bernd Sartorius, group manager of Terahertz Technology at Fraunhofer HHI, and his team have integrated these chips in fiber-coupled flexible emitter and detector modules. As Bernd Sartorius explains, "Our system takes terahertz out of the lab environment. Our terahertz sensors can be flexibly integrated in a huge variety of fabrication and monitoring workflows. Control and evaluation is done by the laptop."

Terahertz at work

Monitoring the production and processing of plastics is one important area of use for terahertz sensors. In the food industry mobile complete systems can be used to scan packaging and foodstuffs to monitor the quality of contents. Unlike metal detectors, this system can even detect non-metallic materials like splinters of glass in chocolate.

The new technology is also ideal for the scanning of letters and packets to detect possible bio-weapons or explosives. The photo below shows a powder-filled plastic pouch between two sections of corrugated cardboard representing part of a packet. The THz emitter and detector heads developed by Fraunhofer HHI conduct a THz spectroscopic analysis of the powder. The THz transmission spectrum on the left shows an absorption band which identifies the powder as harmless lactose.

THz irradiates packages like corrugated cardboard boxes and can make a spectroscopic analysis of the materials inside. (Photo: Fraunhofer HHI)

THz combines the characteristics of radio waves and infrared light

Mobile and affordable – terahertz as a complete system

Developed by Fraunhofer HHI, the "TeraWave Time Domain Spectrometer" complete system packs all the components and processes needed (Photo: Fraunhofer HHI)

A new chip from Fraunhofer HHI tones up THz for real-world usage

Fraunhofer HHI THz sensor systems can be flexibly integrated into fabrication workflows

Terahertz at work

Brainy Smart Terahertz (THz) Detector

2012-03-01T05:27:00.003-08:00

http://fllinnovationaward.firstlegoleague.org/brainy-smart-terahertz-thz-detector

MY NOTE: I just saw this, it's another sign, of how wide spread interest in THz is becoming. (http://halfadozennerds.webs.com/ourresearch.htm)

Team Name:

The Brainy Bunch

Team Number:

3186

Team Location:

Great Falls Virginia 22066

United States

Team Description:

We are a FLL team of six eighth graders from Kilmer Middle School in Vienna, Virginia who are passionate about science, technology and exploring new ideas to help our community. We want to make a difference even if it is small one in this world! We learned a lot from scientists around the world and enjoyed meeting people during our community outreach efforts. We worked with elementary school children, girl scouts, dairy farm owners and grocery stores to create food safety and FLL/JFLL awareness. We discovered how enjoyable it is to learn from others. The Brainy Bunch members’ countries of ethnicity includes India, China, Germany, Poland, France, Ireland and Korea, which resulted in an innovative global solution that applies to the U.S. and other countries. We hope our solution helps to prevent future suffering and deaths related to food-borne illnesses. Our motto is, “Raising food safety awareness is the first step toward prevention of food-borne illnesses all around the world."

Brief Submission Description:

Rise in Global food trade trend comes with its share of challenges! Our solution targets to improve the current Global food safety systems to ensure delivery of safe food to consumers worldwide. The Terahertz (THz) detector uses THz Spectroscopy to detect contaminants along the entire food supply chain. The device uses non-ionizing pulses that are safe and non-destructive. The non-contact sensor picks up transmitted signals from the food sample and creates a unique data to rapidly identify presence of bacteria, anthrax spores, pesticides, drugs, adulterants, metals, and aflatoxins. This technology is being utilized by Homeland security to detect explosives and the Pharmaceutical industry for quality control. Currently, scientists are developing a LED that is able to emit THz frequencies at the desired rate of picosecond bursts. This will eliminate the bulk of the cost further, lowering it to around $500 for the prototype. Once mass produced, the cost is likely drop to less than $100!

Wright State University Terahertz Research Cluster- (with many interesting THz links)

2012-02-29T12:05:00.000-08:00

Terahertz Research Cluster

Dr. Elliott Brown

Dr. Jason Deibel

Dr. Ivan Medvedev

Dr. Doug Petkie

Overview

The WSU Terahertz Research Cluster consists of four core faculty members and their respective research groups. These faculty include Dr. Elliott Brown, the Endowed Chair of Terahertz Sensing and Professor of Physics and Electrical Engineering, who has extensive expertise in millimeter wave and terahertz device physics, science, and systems. Dr. Jason Deibel, Assistant Professor of Physics and Electrical Engineering, specializing in time-domain spectroscopy using ultrafast lasers and computational electromagnetics. Dr. Ivan Medvedev, Assistant Professor of Physics, who specializes in gas phase spectroscopy and the development of spectrometers. Dr. Doug Petkie, Associate Professor of Physics and Electrical Engineering, who focuses on millimeter and submillimeter wave continuous-wave systems for radar, imaging and spectroscopy applications. Overall, the research cluster studies a wide range of phenomenology and develops applications in the areas of spectroscopy, imaging, microscopy, and non-destructive evaluation techniques. The group has over 6000 sq ft laboratory space on campus and also has access to space at the IDCAST facility. The research group is well equipped with instrumentation and methods covering most THz techniques.

The Terahertz Collaborative Research Center (THz CRC) is a cohort of university and government laboratories and research groups in the greater Dayton Region that have research efforts focused on millimeter wave and terahertz basic and applied science and engineering. This collaborative effort is made possible by the State of Ohio’s Third Frontier Program through awards to the Institute for the Development and Commercialization of Advanced Sensor Technology (IDCAST) and the Ohio Academic Research Cluster for Layered Sensing (OARCLS). The research groups work closely with many companies, particularly those associated with IDCAST, such as Traycer Diagnostics Systems and Photon-X, to acceleration the commercialization of THz technology.

THz CRC Related Links: (not a complete list!)

The microwave/millimeterwave/THz portion of the research cluster and other collaborators includes several faculty members at universities local to the Dayton, research scientists at AFRL, and several Ohio companies. Some of the partners include:

Wright State University [Colleges of Science and Mathematics (Physics) and College of Computer Science and Engineering (Electrical Engineering)]

Elliott Brown (Endowed Chair in THz Sensing and Professor of Physics and Electrical Engineering) Devices, systems/applications, multi-modal sensing and advanced materials.
Doug Petkie (Associate Professor of Physics and Electrical Engineering) – continuous-wave mmwave/THz electronic experimental techniques, imaging, radar and gas phase spectroscopy.
Jason Deibel (Assistant Professor of Physics and Electrical Engineering) – Time-Domain Spectroscopy experimental techniques, imaging, materials science, and computational EM modeling.

Ivan Medvedev (Assistant Professor of Physics and Electrical Engineering) –
Gregory Kozlowski (Associate Professor of Physics) – Microwave evanescent imaging and spectroscopy, nano sensing materials, and superconductivity.

Lok Lew Yan Voon (Professor of Physics and Chair of Physics) – Band Structure Theory and Applications to Nanostructures, Computational Electromagnetics for Metamaterials
Yan Zhuang (Assistant Professor of Electrical Engineering) – NEMs, MEMs, high frequency and microwave components, and device physics.
Brian Rigling (Associate Professor of Electrical Engineering) – Signal processing for radar and imaging exploitation.

University of Dayton (Electro-optics Program and Department of Physics)
- Peter Powers (Professor of Physics and Electro-Optics)
- Joe Haus (Professor and Director of Electro-Optics)
- Qiwen Zahn (Associate Professor of Electro-Optics)
University of Dayton Research Institute
- Gil Pacey (Senior Research Scientist)
- Anita Taulbee (Research Scientist)

Ohio State University (Department of Physics)
- Frank De Lucia (Distinguished University Professor), Microwave Lab

Miami University

Air Force Institute of Technology (Department of Engineering Physics)
- Michael Hawks (Assistant Professor of Physics)

Air Force Research Laboratory
- Propulsion Directorate – Non-destructive spectroscopy and imaging techniques on propulsion related systems.
- Materials and Manufacturing Directorate – Development of materials for THz sources and detectors, systems for non-destructive imaging of air craft structures, electronic and optical properties of new materials.
- Sensors Directorate – Development of THz sources (QCL).
- Human Effectiveness Directorate – Terahertz human signatures and bio-signatures. Health and safety studies associated with mmwaves and THz.

LOCI at UD - Laser and Optical Communications Institute
ElectroScience Laboratory at OSU
Several companies through Third Frontiers programs and other companies through SBIRs.

Please send any comments to thz-physics'at'wright.edu or to Drs. Brown, Deibel, Medvedev or Petkie.

Researchers fire up record speed wireless data bridge

2012-02-28T06:48:00.000-08:00

Bridging the ‘last mile'

By Robert Jaques

Tue Feb 28 2012, 10:40

A RESEARCH TEAM in Germany yesterday claimed to have solved the knotty problem of delivering high-speed digital communications over the "last mile" into homes and businesses located in isolated or rural areas.

The researchers showed off a wireless data bridge that transmits digital information at a record breaking speed of 20Gbit/sec. The data turbo boost was, they explained, achieved by using higher frequencies than those typically used in mobile communications - the wireless bridge operates at 200GHz, two orders of magnitude greater than cell phone frequencies.

"An inexpensive, flexible, and easy-to-implement solution to the 'last mile' problem is the use of wireless technology," said Swen Koenig, a researcher at Karlsruhe Institute of Technology's (KIT) Institute of Photonics and Quantum Electronics.

"Instead of investing in the cost of digging trenches in the ground and deploying ducts for the fibres, data is transmitted via the air-over a high-speed wireless link."

The setup sees the optical fibre infrastructure used up to its ending point and then connected to a wireless gateway. This gateway converts the optical data to electrical millimetre-wave signals that feed an antenna. The transmitting antenna "illuminates" a corresponding receiving antenna. At the receiving point, the electrical signal is directed toward its final destination, either using another wireless channel in a relay technique via copper wire or a coaxial TV cable or with an optical fibre.

A major issue in integrating a wireless link into a fibre optic environment is to ensure that the wireless link supports data rates comparable to those of the optical link - ideally about 100Gbit/sec, according to Igmar Kallfass, a researcher and the project's leader at the Fraunhofer Institute for Applied Solid State Physics IAF, as well as a professor at KIT.

"Besides optoelectronic conversion, no further processing must be involved before the signals reach the antenna. This also holds for the receiving part in a reversed sequence," Kallfass said.

He added that such multi-gigabit wireless transmission demands multi-GHz bandwidths, which are only available at much larger frequencies than mobile communications normally use. Millimeter-wave frequencies - radio frequencies in the range of 30-300GHz - fulfill this need. By comparison, laser light, as used in optical communications, provides bandwidths of many terahertz (THz).

After the first fibre span, the optical signal is received in the first wireless gateway and converted to an electrical signal. The electronic up-converter module is then used to encode the electrical signal onto a radio frequency carrier of 220 GHz. This modulated carrier then feeds the antenna that radiates the data. The antenna of a second wireless gateway receives the signal.

In the first indoor experiment, the wireless transmission distance was limited to 50 centimetres, but this has now been boosted to 20 metres, notes Kallfass.

The team will present its research at the Optical Fiber Communication Conference and Exposition / National Fiber Optic Engineers Conference (http://www.ofcnfoec.org), taking place next month in Los Angeles. µ

Source: The Inquirer (http://s.tt/15T1w)

Dr. David Zimdars of Picometrix -2012 In-Space Non-Destructive Inspection Technology Workshop Presenter

2012-02-28T06:08:00.002-08:00

2012 In-Space Non-Destructive Inspection Technology Workshop Presenter

Dr. David Zimdars
Picometrix, LLC
Manager of Terrahertz R&D
dzimdars@picometrix.com
(734) 865-5639

www.picometrix.com Session 3A Presentation 3
"Hand Held Terahertz Imaging"
Demo: No | Poster: No
One-on-One Table: No

Abstract: Hand held time-domain terahertz (TD-THz) non-destructive evaluation (NDE) systems can be used to inspect space flight structures such as inflatable space habitats, thermal protection systems (TUFI-type tiles, SOFI TPS), and other components for voids, disbonds, and damage such as tearing and micro-meteorite impact. THz radiation in the range of 0.1 THz to 3 THz can penetrate these materials, and can be used to generate sub-surface images of these otherwise opaque or hidden structures. TD-THz reflection tomography is a single sided method, so it can inspect an inflatable habitat from the inside. Because the method is electromagnetic, it is inherently non-contact, and can penetrate vacuum (unlike ultrasound tomography), which is a significant advantage for the space based inspection of delicate structures such as polyurethane or silica foam TPS. The method of TD-THz reflection tomography employs near single-cycle sub-picosecond electromagnetic impulses that are generated and detected by the TD-THz instrument. These THz impulses are focused onto the object to be inspected. A small portion of the THz impulse reflects from the boundary of each material interface. These reflected pulses are separated in time, proportional to the thickness between the layers. The reflected TD-THz waveform is recorded, and the waveform is a representation of the sub-surface structure. In many ways, TD-THz reflection tomography is like an electromagnetic analog to ultrasound tomography (UT).
Background: Dr. David Zimdars is the Manager of Terahertz Research and Development at Picometrix. Since 2001, Dr. Zimdars has been the research and development manager for all terahertz scientific, industrial and homeland security product development contracts, terahertz analytical/imaging applications development, and terahertz manufacturing quality control applications development. He was a co-developer of the compact fiber optic coupled T-Ray 4000 modular time domain terahertz instrumentation system. Picometrix T-Ray 4000 and QA-1000 terahertz imaging systems have been deployed by NASA Michoud / Lockheed Martin to scan the space shuttle external fuel tank sprayed on foam insulation and orbiter thermal protection systems. The QA-1000 has been awarded the 2004 Photonics Spectra Circle of Excellence Award. He was a co-developer of the T-Ray 2000 THz spectroscopy and imaging system. Released in the in fall 1999, the T-Ray 2000 was the world’s first commercially available time domain THz instrument. The T-Ray2000, due to its unique capabilities and innovative fiber coupled design, was given an R&D 100 award for and a Photonics Spectra award. He currently has over 32 papers and publications and several patents and patents pending.
Education:
Stanford University, Ph.D. (Chemistry - Chemical Physics), 1996
Rocky Mountain College, B.S. (Chemistry), 1989
Professional Experience:Pres-2001 Manager of Terahertz R&D, Picometrix, LLC, Ann Arbor, MI
2001-1999 Research Scientist, Picometrix Inc., Ann Arbor, MI
1999-1996 Postdoctoral Researcher, Dept. of Chem., Columbia Univ., New York

Find this article at:

http://www.nasa.gov/offices/nesc/workshops/in_space_Bio_zimdars.html

My Note: Thanks for finding this link to:

bucktailjig05

Optical Terahertz Sensing Session at the 2012 OSA Optical Sensors Topical Meeting

2012-02-27T16:39:00.001-08:00

Advancing the Science and Technology of Light

The submission deadline for the 2012 OSA Optical Sensors meeting has been extended. The new deadline is 17:00 GMT (12 pm EST) on March 5th.

Please consider submitting an abstract for consideration for oral or poster presentation to the Optical Terahertz Sensing Session at the 2012 OSA Optical Sensors Topical Meeting.
http://www.osa.org/meetings/topical_meetings/sensors/default.aspx.

The meeting will take place from June 24th – 28th, 2012 in Monterey, California and will be co-located with the other following meetings:
Imaging Systems and Applications
Applied Industrial Optics: Spectroscopy, Imaging, and Metrology
Optical Remote Sensing of the Environment
Optical Sensors
Computational Optical Sensing and Imaging
Optical Fabrication and Testing

Topics for the Terahertz Sensing sessions include but are not limited to
- Sources & Detectors
- THz Spectroscopy for Sensing
- THz Imaging
- THz Sensing for Safety and Security Applications
- THz Sensing in Industrial Environments
- THz Components (waveguides, filters, metamaterials, polarizers, etc.)
- Commercial systems

Submissions can be made at https://account.osa.org/connect.aspx?url_success=http%3A%2F%2Fimaging2012.abstractcentral.com%2Flogin%3FNEXT_PAGE%3DWELCOME%26PRE_ACTION%3DLOGIN%26ssoToken%3D{token}.

Invited speakers for the Terahertz Sensing sessions:
Richard Averitt (Boston University)
Henry Everitt (Duke University & US Army Research)
Qing Hu (Massachusetts Institute of Technology)
Eddie Jacobs (University of Memphis)
Martin Koch (Phillips Marburg University)
Yun-Shik Lee (Oregon State University)

---------------------------------------------------------------------
Jason A. Deibel, Ph.D.
Assistant Professor
Department of Physics, Wright State University
Fawcett Hall 257
Office Phone:    (937) 775-2148
Office Fax:        (937) 775-2222
Lab Phone:        (937) 775-3104 (Library Annex 070)

TeraTOP- focus on CSEM, Centre Suisse d'Electronique et de Microtechnique

2012-02-26T09:03:00.001-08:00

General description

CSEM, Centre Suisse d'Electronique et de Microtechnique, founded in 1984, is a private R&D center specialized in micro- and nanotechnology, system engineering, micro- and optoelectronics, as well as communications technologies. CSEM has more than 400 employees in Switzerland and 54M€ in revenues (2009). In the field of electronic imaging and integrated circuits CSEM is focused on the development of low-power ICs, imaging systems of ultimate performance, and imagers with on chip and pixel-level signal-processing functionality. Specific know-how embraces thorough knowledge of semiconductor physics and devices, analogue and mixed-signal circuit design, analogue and digital control electronics for image sensors, as well as firmware, algorithmic, software, optics and system engineering for photo detector systems.

Role / activity in the project

CSEM is the coordinator of the TeraTOP project. In addition, CSEM will lead the WP4 on the development and characterization of the low-noise readout circuit (ROIC) of the Terahertz imaging detector.

People involved in the project

Nicolas Blanc, received his PhD in Physics in 1992 from the EPFL in Lausanne, Switzerland. He also holds an executive MBA from the RH Smith School of Business of the University of Maryland (USA). He worked in the field of Nanodevices at IBM Zurich Research Laboratory and in MEMS at the Institute of Microtechnology at the University of Neuchâtel, Switzerland. In 1996 he joined the Paul Scherrer Institute in Zürich, Switzerland. His primary responsibilities were in the management of R&D projects in solid-state image sensors. From 1997 to 2004 he worked at CSEM, first as a Project Manager and then as the Section Head of the Image Sensing Group. Since 2004 he is heading CSEM’s Photonics Division in Zurich. Nicolas Blanc and his team won several awards, the most renown being the “EuroCase IST Grand Prize 2004” (€ 200’000) for the development of miniaturized 3D cameras for high performance and mass-market applications. Nicolas Blanc is member of the IEEE and SPIE, and board member of the association sensors.ch. He has co-authored more than 50 papers and 2 book chapters.

Stephan Beer, received his PhD in 2006 from the University of Neuchâtel, Switzerland, for “Real-time photon-noise limited optical coherence tomography based on pixel-level analogue signal processing”, a research project he carried out at the CSEM SA. In 2006 he joined CSEM’s Photonics Division to work as R&D engineer in several projects in the field of image sensing, especially smart-pixel imagers, high-speed, and low-noise imaging. Since 2010 he is the deputy of the head of the image sensing group at CSEM and responsible of the design activities in the field of image sensors.

André Bischof, received his M.S degree in 1996 from the Swiss Federal Institute of Technology (ETH Zurich), Switzerland. From 1996 to 1998, he worked with Philips Semiconductors in Zurich as a design engineer responsible for the design of VLSI circuits for telecom applications. In 1998, he joined Conexant Systems in Newport Beach, California, where he focused on the design of key signal processing circuits for personal communication products. From 2000 to 2005, he worked as a project leader at BridgeCo AG in Dübendorf, Switzerland. He was leading the product development of System On Chip (SoC) ASICs for multimedia products with first time success story and followed companion devices. In 2005, he joined G-Lab GmbH in Zurich, Switzerland, where he took the technical lead for the development of the “Geneva Sound System” product family (all-in-one home stereo audio systems), and got promoted to chief technical officer (CTO). Since 2009, he is working at CSEM’s Photonic Division as a R&D engineer and project leader.

Contact

André Bischof Senior R&D Engineer
andre_bischof@csem.ch
T +41 44 497 1454
F +41 44 497 1400

3rd EOS Topical Meeting on Terahertz Science & Technology (TST 2012)

2012-02-25T18:59:00.000-08:00

Location: Kaiserstejnsky Palace, Prague, Czech Republic
Duration: 17 June 2012 – 20 June 2012

General Chairs:
Petr Kužel – Institute of Physics of the ASCR / Czech Republic
Peter Uhd Jepsen – Technical University of Denmark / Denmark

Program Committee:
Richard Averitt – Boston University / United States
Jean-Louis Coutaz – Université de Savoie / France
Guilhem Gallot – Ecole Polytechnique / FR
Rupert Huber – Universität Konstanz / Germany
Michael Johnston – University of Oxford / United Kingdom
Martin Koch – Philipps-Universitaet Marburg / Germany
Chiko Otani – Riken Sendai / Japan
Paul C.M. Planken – Delft University of Technology / Netherlands
Masayoshi Tonouchi – Osaka University / Japan
Alessandro Tredicucci – NEST, CNR-NANO / Italy
Karl Unterrainer – Technische Universität Wien / Austria

Topics

Emission of THz radiation (QCLs, HEMTs, FELs, synchrotrons, nonlinear optics etc.)
Detection of THz radiation (quantum dots, single photon detectors, time-gated, HEMTs etc.)
THz integrated optics, waveguiding, plasmonics, metamaterials, photonic crystals
Interaction of THz radiation with matter (dielectrics, semiconductors, nanostructured materials, liquid-state dynamics, chemistry, biology, ultrafast spectroscopy etc.)
Nonlinear phenomena induced by THz radiation
THz far-field and near-field imaging, THz microscopy and microspectroscopy
Remote sensing of gases and chemical / biological agents
THz applications (security, telecom, remote detection etc.)

Keynote Speaker

Xi-Cheng Zhang, University of Rochester (US)

Masterclass Speakers

Edmund H. Linfield, University of Leeds (GB)
Keith A. Nelson, Massachusetts Institute of Technology (US)

Invited Speakers

Dave Cooke, McGill University (CA)
Kodo Kawase, Nagoya University (JP)
Junichiro Kono, Rice University (US)
Oleg Mitrofanov, University College London (GB)
Hynek Nemec, Academy of Sciences of the Czech Republic (CZ)
Alexej Pashkin, University of Konstanz (DE)
Marco Rahm, Technical University of Kaiserslautern (DE)
Giacomo Scalari, ETH Zurich (CH)
Miriam Vitiello, National Research Council (IT)

Venue
Prague, the capital of the Czech Republic, is a most valuable historical city reserve. In 1992, the historical core of the city covering 866 hectares was listed in the UNESCO World Cultural and Natural Heritage Register. Prague represents a unique collection of historical monuments dominated by the Prague Castle which towers high above the city (www.praguewelcome.cz).
TST 2012 will take place at Kaiserstejnsky Palace which is located in the Prague Lesser Town and has been hosting events for more than three centuries.

Its total reconstruction began under the architects Zden?k Pokorný and Jaroslav B?lský in 1977, and it was registered a UNESCO heritage site in 1981. Restitution procedures were completed and the palace returned to its original owners in 1997.

For more information see

http://www.myeos.org/events/tst2012

https://www.facebook.com/groups/21589817360/

Technique Creates Piezoelectric Ferroelectric Nanostructures

2012-02-24T21:07:00.003-08:00

Newswise — Researchers have developed a “soft template infiltration” technique for fabricating free-standing piezoelectrically active ferroelectric nanotubes and other nanostructures from PZT – a material that is attractive because of its large piezoelectric response. Developed at the Georgia Institute of Technology, the technique allows fabrication of ferroelectric nanostructures with user-defined shapes, location and pattern variation across the same substrate.
The resulting structures, which are 100 to 200 nanometers in outer diameter with thickness ranging from 5 to 25 nanometers, show a piezoelectric response comparable to that of PZT thin films of much larger dimensions. The technique could ultimately lead to production of actively-tunable photonic and phononic crystals, terahertz emitters, energy harvesters, micromotors, micropumps and nanoelectromechanical sensors, actuators and transducers – all made from the PZT material.
Using a novel characterization technique developed at Oak Ridge National Laboratory, the researchers for the first time made high-accuracy in-situ measurements of the nanoscale piezoelectric properties of the structures.
“We are using a new nano-manufacturing method for creating three-dimensional nanostructures with high aspect ratios in ferroelectric materials that have attractive piezoelectric properties,” said Nazanin Bassiri-Gharb, an assistant professor in Georgia Tech’s Woodruff School of Mechanical Engineering. “We also leveraged a new characterization method available through Oak Ridge to study the piezoelectric response of these nanostructures on the substrate where they were produced.”
The research was published online on Jan. 26, 2012, and is scheduled for publication in the print edition (Vol. 24, Issue 9) of the journal Advanced Materials. The research was supported by Georgia Tech new faculty startup funds.
Ferroelectric materials at the nanometer scale are promising for a wide range of applications, but processing them into useful devices has proven challenging – despite success at producing such devices at the micrometer scale. Top-down manufacturing techniques, such as focused ion beam milling, allow accurate definition of devices at the nanometer scale, but the process can induce surface damage that degrades the ferroelectric and piezoelectric properties that make the material interesting.
Until now, bottom-up fabrication techniques have been unable to produce structures with both high aspect ratios and precise control over location. The technique reported by the Georgia Tech researchers allows production of nanotubes made from PZT (PbZr0.52Ti0.48O3) with aspect ratios of up to 5 to 1.
“This technique gives us a degree of control over the three-dimensional process that we’ve not had before,” said Bassiri-Gharb. “When we did the characterization, we saw a size effect that until now had been observed only in thin films of this material at much larger size scales.”
The ferroelectric nanotubes are especially interesting because their properties – including size, shape, optical responses and dielectric characteristics – can be controlled by external forces even after they are fabricated.
“These are truly smart materials, which means they respond to external stimuli such as applied electric fields, thermal fields or stress fields,” said Bassiri-Gharb. “You can tune them to behave differently. Devices made from these materials could be fine tuned to respond to a different wavelength or to emit at a different wavelength during operation.”
For example, the piezoelectric effect could permit fabrication of “nano-muscle” tubes that would act as tiny pumps when an electric field is applied to them. The fields could also be used to tune the properties of photonic crystals, or to create structures whose size can be altered slightly to absorb electromagnetic energy of different wavelengths.
In fabricating the nanotubes, Bassiri-Gharb and graduate student Ashley Bernal (currently an assistant professor at the Rose-Hulman Institute of Technology) began with a silicon substrate and spin-coated a negative electron-beam resist material onto it. A template was created using electron-beam lithography, and a thin layer of aluminum oxide was added on top of that using atomic layer deposition.
Next, the template was immersed under vacuum into an ultrasound bath containing a chemical precursor solution for PZT. The structures were pyrolyzed at 300 degrees Celsius, then annealed in a two-step heat treating process at 600 and 800 degrees Celsius to crystallize the material and decompose the polymer substrate. The process produced free-standing PZT nanotubes connected by a thin layer of the original aluminum oxide. Increasing the amount of chemical infiltration allows production of solid nanorods or nanowires instead of hollow nanotubes.
Though the researchers used electron beam lithography to create the template on which the structures were grown, in principle, many other chemical, optical or mechanical patterning techniques could be used for create the templates, Bassiri-Gharb noted.
In studies done in collaboration with researchers Sergei Kalinin and Alexander Tselev of the Center for Nanophase Materials Sciences at the Oak Ridge National Laboratory, the devices produced by the soft template process were analyzed with band-excitation piezoresponse force microscopy (BPFM). The technique allowed researchers to isolate properties of the AFM tip from those of the PZT sample, allowing analysis in sufficient detail to detect the size-scale piezoelectric effects.
“One of our most important observations is that these piezoelectric nanomaterials allow us to generate a factor of four to six increase in the extrinsic piezoelectric response compared to the use of thin films,” said Baassiri-Gharb. “This would be a huge advantage in terms of manufacturing because it means we could get the same response from much smaller structures than we would have had to otherwise use.”
The Center for Nanophase Materials Sciences is one of the five Department of Energy (DOE) Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale that are supported by the DOE Office of Science. Together, the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov/bes/suf/user-facilities/nanoscale-science-research-centers/.
Research News & Publications Office
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 314
Atlanta, Georgia 30308 USA
Writer: John Toon
Permalink to this article

Dr. Irl Duling, Director of Terahertz Business Development, at Picometrix, discusses the AGFM announcement, regarding non-destructive inspection of aircraft radomes

2012-02-23T07:08:00.001-08:00

Randy,
Thanks for posting the link to the AGFM announcement.
We have been working with them for a number of years, looking at damage in aircraft radomes.
The IRPC project involves a number of different technologies integrated into a unified repair cell.
There are technologies to:
1.Digitize the surface profile of the radome (laser based),
2.determine the possible locations of damage (shearography),
3.determine the exact location and depth of the damage (THz),
4.automated machining to cut out the damage (6-axis robot),
5.laser projection to give a visual indication of where the repair should be made,
6.automated ply cutting to pre-cut the fiberglass for the repair.

We were selected from among a number of different technologies to be the "secondary NDI". That means that we follow-up the initial inspection to provide more precise information.

[It is my feeling that THz could perform the entire inspection without the need for the technologies in 1 and 2, because although we may not be a "global imaging" technology, we could digitize and image the entire radome faster than they can digitize, rig for and perform shearography, and have us image the areas indicated.]

Shearography can only determine the general location. THz is used to provide the specific location and the depth of the damage. Our sensor was mounted on the same 6-axis robot as performed the automated scarfing (cutting out of the damage).

The next steps will be to begin the deployment of an initial repair cell (probably with just digitization and shearography), and the rest of the technologies added at a later date.

(Irl Duling)

Focus on:Centre for Terahertz Science and Engineering

2012-02-22T07:25:00.000-08:00

http://www3.imperial.ac.uk/terahertz

Welcome to the Centre for Terahertz Science and Engineering (CTSE), established in February 2012. This Imperial College London centre is in partnership with the UK's RAL Space Millimetre Wave Technology Group and is located within the Faculty of Engineering at Imperial College London. Our main goal is to become the leading UK platform for terahertz (THz) science and engineering, dedicated to the following:

Research and development of new materials and their electromagnetic characterization for THz applications
Research and development of passive components and active devices, based on advanced functional materials and micro/nano-fabrication processing technologies
Exploration of new applications in the areas of telecommunication and electromagnetic sensing for bioengineering, security and defence applications
Interdisciplinary education and training in electromagnetic material characterization, millimetre-wave and terahertz engineering, device/circuit simulation and metrology.

In addition, CTSE provides:

A forum to stimulate more formal inter-departmental/faculty collaboration at Imperial College London, ensuring cross-fertilisation between different fields of research.
A joint facility for external collaboration with academia, research laboratories, government agencies and industry.
A forum for the exchange of ideas between researchers, as well as a focal point for the exchange of expertise and resources.
A venue for educational teaching activities (e.g. joint masters degree courses and Summer Schools).

In a two step NDI process, Laser Shearography ( Steinbichler) chosen as primary NDI inspection,for aerospace industry, with Terahertz NDI (Picometrix) chosen as second step

2012-02-21T07:54:00.000-08:00

Preparation Cell (IRPC) consortium, continues to progress its efforts to develop systems that detect and repair damage in composite aerostructures.

http://www.compositesworld.com/news/american-gfm-aerospace-repair-process-update(2)

American GFM (AGFM, Chesapeake, Va., USA), part of the worldwide GFM machine tool organization, has been at the forefront of composite repair for aerostructures for several years, leading and coordinating the Inspection and Repair Preparation Cell (IRPC) consortium. This multi-company, multi-technology effort has focused on development of an automated system that allows for fast defect detection, scarfing and repair of composite structures of all types. The goal, as the Boeing 787 enters the field, and as the first Airbus A350 XWB enters assembly, is to establish a repair process that not only helps airlines maintain a healthy aerostructure, but do so with minimal aircraft downtime.

AGFM recently hosted an event at its Chesapeake facility to demonstrate the current state of the repair technology it has developed with the IRPC. Frank Elliott, advanced initiatives coordinator at AGFM, says the repair strategy developed relies on three primary functions: Defect detection, scarfing and repair. The demonstration focused primarily on detection and scarfing.

For the demonstration, AGFM had on hand the section of a radome panel from a C-130 aircraft. The panel, about 2 ft/0.6m wide and 3 ft/0.9m long, was about 40 years old and comprised a sandwich structure of honeycomb core surrounded front and back by a glass fiber laminate skin.

A traditional tap test of the panel indicated several potential locations of defects, which were marked. This was followed by another assessment using non-destructive inspection (NDI) via laser shearography provided by Steinbichler Vision Systems (Plymouth, Mich., USA). Defects detected during this inspection were also marked — most of which did not coincide with the tap test results.

With possible defect locations identified, the radome panel was placed on a 25,000-rpm router (Fig. 1), which was used to scarf potential defect locations. The first site, identified via laser shearography, was an area about 3 inches/76 mm in diameter. It was machined in three passes, based upon a 50:1 scarfing angle with a depth of 0.007 inch/0.18 mm on each pass. The scarfing revealed two delamination sites between the laminate and the core (see Fig. 2), confirming results of the laser shearography. One more pass was made over the site, increasing the depth of the scarfing by 0.007 inch and revealing even more damage from delamination (Fig. 3).

A second site, also identified via laser shearography, was machined next. This was an angled scarf, which involves routing out the damaged/defective material, down through both the outer skin and the honeycomb core to the inner skin; then angle scarfing the outer skin at the 50:1 angle in order to enable an acceptable repair. An obvious flaw was not revealed, but inside the hole created by the router, it was revealed that there had been a resin drip, which might have been flagged by NDI as a potential flaw.

Flaw detection is the biggest challenge the IRPC faces. Elliott notes that there is “no absolute in NDI,” and reports that a variety of technologies have been evaluated by the IRPC. Laser shearography was chosen as the global (primary) NDI technology because it provides a quick indication of areas that contain anamolies that require further inspection by a local (secondary) NDI process, to determine more precisely the location, boundary and depth of the defects. The secondary NDI technology chosen is Terahertz NDI, provided by Picometrix LLC (Ann Arbor, Mich., USA), because of its accuracy, resolution and speed of inspection.

Elliott, AGFM and the IRPC will continue to develop, fine-tune and integrate its processes, and in the meantime, the program has also attracted interest from other aerospace manufacturers looking for viable repair technologies.

SRC and UT Dallas Show Manufacturability of Affordable Terahertz Receiver, Opening New Industry Segment for Consumer Applications

2012-02-21T06:48:00.000-08:00

A one-pixel CMOS terahertz image chip (left) can see through solid objects, here showing the inner workings of an old-school floppy disk.

RESEARCH TRIANGLE PARK, N.C., Feb 21, 2012 (BUSINESS WIRE) -- Semiconductor Research Corporation (SRC), the world's leading university-research consortium for semiconductors and related technologies, and UT Dallas today announced research results that show circuits operating at the terahertz (THz) range can be affordably manufactured in complementary metal-oxide semiconductor (CMOS) silicon. The findings set the stage for new industry segments that create electronic applications not yet available for everyday use and that offer portability and cost effectiveness.

On the spectrum of wavelengths, THz waves occur at the far end of the infrared band, just above the millimeter waveband. Compared to other wavelengths, THz are considered to have numerous desirable properties. For instance, in contrast with x-ray, THz is intrinsically safe, non-destructive and non-invasive. However, THz was previously impractical for mainstream consumer uses due to cost.

With the breakthrough presented by SRC and UT Dallas, THz circuits can now be manufactured within economical CMOS technologies. As a result, the sensitive THz portion of the spectrum can become accessible for use in everyday products.

A key component of THz systems is a receiver that UT Dallas has shown can be manufactured affordably. Employing Schottky diodes in 130 nanometer (nm) CMOS with higher cut-off frequency than MOS transistors, the new detector's sensitivity allows reception of signals that are smaller than those previously achieved using MOS transistors in 65nm CMOS. The Schottky diodes can be fabricated without any process modifications.

"Our new technology can take the cost for producing THz systems down from hundreds of thousands of dollars to only a few hundred dollars," said Professor Ken O, lead researcher for SRC's program at UT Dallas. "The impact will be huge. The collective chip industry can literally light up a portion of the wavelength spectrum so all can benefit from the applications."

Multiple communities have expressed interest in leveraging these new THz capabilities, including defense, medical, industrial process control and public and industrial safety.

"The need for THz communications is great, and our progress holds tremendous potential for enhancing the lives of many -- both in a preventative and curative nature," said Betsy Weitzman, SRC executive vice president. "The results we have here will broadly enable many opportunities for consumers and the semiconductor industry."

THz can enable a wide range of uses such as monitoring for toxic molecules in the air, breath analyses for disease diagnostics, imaging cavities without use of the more harmful x-rays, imaging cancerous cells, controlling industrial processes and conducting remote high resolution imaging and high bandwidth communication. Until now, there has been no economical way to make the systems that can support these applications.

"SRC supports a comprehensive THz research effort through various programs, and advances from the projects will impact the electronics industry over the next decade," said Dale Edwards, a GLOBALFOUNDRIES assignee at SRC.

More information about the research is published in the paper titled, "280GHz and 860GHz Image Sensors Using Schottky-Barrier Diodes in 0.13um Digital CMOS," presented today at the annual International Solid-State Circuits Conference (ISSCC) in San Francisco. The research is funded through SRC and performed at the RF and THz laboratory of Texas Analog Center of Excellence at UT Dallas. The paper is co-authored by Ruonan Han, a former student of Professor O, and Yaming Zhang, Yongwan Kim, Dae-Yeon Kim and Sam Shichijo at UT Dallas.

About SRC

Celebrating 30 years of collaborative research for the semiconductor industry, SRC defines industry needs, invests in and manages the research that gives its members a competitive advantage in the dynamic global marketplace. Awarded the National Medal of Technology, America's highest recognition for contributions to technology, SRC expands the industry knowledge base and attracts premier students to help innovate and transfer semiconductor technology to the commercial industry. For more information, visit www.src.org .

SOURCE: Semiconductor Research Corporation

Terahertz Pulse Generates 1,000-Fold Increase in Electron Density

2012-02-18T23:56:00.000-08:00

http://int.saci.kyoto-u.ac.jp/?p=2336
The study of carrier multiplication has become an essential part of many-body physics and materials science. Assistant Prof Hideki Hirori and co-workers observed that when exposed to a single-cycle electric field pulse at the 1000 GHz (terahertz) frequency range, a sample of standard semiconductor material (gallium arsenide, GaAs) burst an avalanche of electron-hole pairs (excitons) 1,000-times more abundant than initial states only on the picosecond (10-12 s) time scale. The observed bright luminescence associated with carrier multiplication suggests that carriers coherently driven by a strong electric field can efficiently gain enough kinetic energy to induce a series of impact ionizations. These just-released results with the world strongest terahertz pulses demonstrate the rich potential that lies in the study of terahertz radiation.

This carrier multiplication directly affects nonlinear transport phenomena in ultra-high-speed transistors and plays a key role in designing efficient solar cells and electroluminescent emitters and highly sensitive photon detectors.

Related Information 1. H. Hirori, K. Shinokita, M. Shirai, S. Tani, Y. Kadoya, and K. Tanaka: Nature Commun. 2, 594 (2011).
2. H. Hirori, A. Doi, F. Blanchard, and K. Tanaka: Appl. Phys. Lett. 98, 091106 (2011).

Microtech Instruments terahertz oscillator delivers 100 GHz spectral width

2012-02-18T07:52:00.000-08:00

The TPO-850 terahertz parametric oscillator delivers up to 0.1 mW of average power, and >150 mW of peak power. Its central frequency of 0.85 THz and spectral width of 100 GHz fit into one of the atmospheric transmission windows, allowing use in terahertz imaging. It is based on a quasi-phase-matched gallium arsenide (GaAs) crystal inside an optical parametric oscillator.
Microtech Instruments
Eugene, OR
sales@mtinstruments.com
PRESS RELEASE

The new TPO-850 Terahertz oscillator generates up to 0.1 mW of average power concentrated in the atmospheric transparency window at 850 GHz complementing recently announced TPO-1500.

Eugene, OR, September 29th, 2011. Microtech Instruments, Inc. announces its new terahertz source complementing its THz source product lines, the Terahertz Parametric Oscillator—TPO-850—which delivers up to 0.1 mW of average power (>150 mW of peak power). Its central frequency of 0.85 THz and spectral width of 100 GHz fit perfectly into one of the atmospheric transmission windows, making it an ideal source for terahertz imaging. While Microtech Instruments’ BWO sources can provide more average power, the high peak power of the TPO-850 makes it suitable for imaging systems employing nonlinear optical effects and also pump-probe or time domain terahertz spectroscopy, while sufficiently high average power makes it suitable for thermal detector array imaging. This makes the TPO-850 a complementary addition to the existing product lines. http://www.mtinstruments.com/thzsources/index.htm

Operation of both the TPO-850 and TPO-1500 are based on difference frequency generation in quasi-phase-matched Gallium Arsenide crystal placed inside an optical parametric oscillator pumped by an ultrafast fiber laser. This second product resulting from our DARPA collaboration and STTR contract with the AFOSR increases our sources for nonlinear imaging systems. Additionally, one should note that either of these systems can be upgraded to operate at both frequencies. This added flexibility is an important feature to be aware of as it only requires a different OC-GaAs crystal and adjustment of the OPO to switch from one frequency to another.

Walter Hurlbut, R&D Manager at Microtech comments, “These new high peak power sources complement our BWO product line well as they add high peak power above what a BWO can provide while still providing significantly higher spectral power density than other optical sources. This narrow band source is ideal for the improving contrast of THz imaging systems based on THz-to-optical upconversion. The narrow band THz source combined with a spectrally narrow ultrafast laser can improve the contrast ratio of an imaging system by several orders of magnitude.”

The TPO-1500 and the TPO-850 complement the electronic terahertz sources manufactured by Microtech Instruments. The electronic terahertz sources are based on backward wave oscillators (BWOs) combined with frequency multipliers, which work well up to 1.4 THz but run out of power at 1.5 THz and above. Also, the TPO-850 and TPO-1500’s high peak power make these sources more suitable for nonlinear optical applications.

Microtech Instruments is a leading manufacturer of terahertz components and systems, including terahertz spectrometers, generators, and detectors. Committed to innovation, Microtech collaborates with leading research organizations worldwide.

For more information, visit www.mtinstruments.com, or contact Renee Isley at sales@mtinstruments.com.

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Teraview imaging modules

2012-02-18T07:44:00.000-08:00

http://www.teraview.com/products/terahertz-pulsed-spectra-3000/terahertz-imaging-modules/index.html

Terahertz Imaging Modules

TPI^TM imaga 2000
TPI™ imaga 2000 yields complete 3D – 360° volumetric imaging of intact tablet coatings and cores. TeraView’s TPI™ imaga 2000 is able to determine the thickness, uniformity, distribution and coverage of simple and complex coatings. Structural features such as cracks, dislocations and delaminations in single and multilayer cores are also revealed. Using this terahertz (THz) imaging system, non-destructive determination of the integrity and performance of finished tablets and cores can be rapidly performed. Traditionally sold as a unique and stand-alone instrument this design has now been integrated into the modular design of the TPS Spectra 3000, allowing to be bought as an imaging module.

Reflectance Imaging Module

This accessory converts the TPS spectra 3000 in to a flat-bed imaging system. Samples as large as 100mm x 100mm can be placed in the unit and raster scanned using a software controlled motorized scanning table. Areas up to 80mm x 80mm can be scanned with a user-selected distance between measurement points and up to 3 mm penetration depth. Using the TeraView supplied Image and Data analysis software, thickness maps and cross sectional images can be generated from the data collected and physical features such as buried cracks, defects and air pockets can be non-destructively detected.

Gantry

Our 0.8 by 0.8 m external gantry is used to performe THz spectroscopy and imaging on a range of large objects and materials. In The emitters and detectors are configured via fibre optics onto the gantry and are easily controlled by the integrated software.

3D THz imaging system
for tablet coatings and cores

Reflectance Imaging
module

Gantry for imaging lar

M Squared Lasers looks to go global

2012-02-17T06:47:00.000-08:00

http://optics.org/indepth/3/2/3
As the UK government strives to rebalance its economy towards manufacturing, M Squared Lasers shows the way with photonics innovation.

Firefly: unique

The combination of a prolonged period of global austerity and the cyclical nature of many photonics markets means that any company reporting close to 100% year-on-year revenue growth since 2008 must be doing something right. M Squared Lasers, a UK-based developer and manufacturer of advanced solid-state laser sources, is one such company with this enviable track record.
The company puts its success down to an approach that it calls “dependable innovation”. Since launching the company in 2006, the management team at M Squared has drawn on its industrial experience to develop a modular platform on which all of its sources are built and has subsequently rolled out three product families that are gaining traction in multiple demanding applications.
It is an approach that has paid many dividends. As well as the impressive growth, the business has also doubled its staffing levels year-on-year, created a US subsidiary, moved to larger headquarters to accommodate its R&D and manufacturing needs, and, most recently, appointed a high-profile chairman in the form of ex-Oclaro executive Peter Bordui. The goal is now to build the Glasgow company into a large-scale global business.
“Our vision is to be the market leader in specific, high-growth applications by providing reliable, hands-free devices in new regions of the spectrum,” Graeme Malcolm, the co-founder and CEO of M Squared, told optics.org. “We have adopted an agile, collaborative and open-minded approach and are now targeting specific established and emerging markets where our products can deliver clear benefits.”
Preparation is everything
Malcolm and managing director Gareth Maker left senior management roles at Coherent Scotland in 2006 to form M Squared Lasers – the duo having previously co-founded Microlase, which the US company acquired in 1999. Although they set out to tackle the lack of laser sources emitting in the mid-infrared and terahertz regions, Malcolm and Maker were also keen to address product design limitations that could deliver value for some more established laser sources and applications in the near-infrared.
“Customers get frustrated by high-cost, hands-on designs that are inflexible in terms of functionality,” said Malcolm. “We wanted to take a more collaborative and customer-oriented approach to laser design and manufacturing focusing on reliability and ease of use that in turn delivers extra value to the customer. The approach has extended to licensing agreements and bringing in experts from other sectors, such as our technical director Bill Miller with his background in consumer electronics.”
The two modular components that form the foundation of all M Squared products are its ICE-BLOC Ethernet-based control systems and its alignment-free, ‘fix-and-forget’ InvarianT optics and mounts. The ICE-BLOC controllers are based entirely on Internet Protocol and allow engineers at M Squared and customers to interrogate their lasers from remote sites. To accompany this, the InvarianT optics enable an enclosed hands-off design.
“These modular components are critical to having reliable laser sources,” commented Malcolm. “They are the kind of thing that should be present in any advanced laser system, regardless of wavelength. For us, the benefit is not having to start from scratch when we develop a new source, bringing products to market faster with high reliability.”
Building on the foundation
The next step was to roll these modular components out into hands-free lasers for established markets. Two families of Ti:Sapphire lasers were launched: the SolsTiS, a tunable CW Ti:S source featuring a narrow linewidth of less than 50kHz, and the Sprite, a highly cost effective, compact tunable ultrafast Ti:S source available in either ~100 fs pulse duration or broadband (100 nm) versions.
Malcolm and M Squared were keen to push these lasers into demanding applications where they would have the edge over the competition. For example, the SolsTiS has been well received by researchers in the academic community pioneering quantum optics and atomic cooling whereas the Sprite has found more commercial applications in fields ranging from multiphoton imaging to defense and security.
Although applications such as atomic cooling may not be large markets, M Squared has rapidly gained significant market share thanks to the class-leading performance of its lasers. In turn, this has generated both revenue and momentum at the company allowing it to commercialize a new product family called Firefly for high-growth markets.
Broad source, multiple applications
M Squared’s Firefly lasers are based on a broadly tunable optical parametric oscillator and two versions have been developed for remote sensing applications. First, a mid-infrared laser that is continuously tunable from around 2 microns through to 5 microns with more than 250 mW of output power - useful for identifying complex chemical and biological species at range - and second, a terahertz source covering 0.6 THz to 3.5 THz.

“We have targeted technology where the same laser source can be applied in multiple market sectors,” commented Malcolm. “Firefly provides wavelengths over a vast range and is equally useful for applications in defense as well as oil and gas.” In terms of defense applications, M Squared has been working on the detection of hostile agents. A significant advance has been the development of a stand-off imager which gives the user a real-time view of a scene at range. “Our ability to go from 2 to 5 microns with a single source that can sweep across a scene and differentiate between complex species is unique,” commented Malcolm. “More recently, we have been exploiting the tuning range and peak power of the Firefly to detect improvised explosive devices, but this work is still early stage.” M Squared has used the same mid-infrared Firefly source and imager for oil and gas applications such as the detection of fugitive emissions from complex pipework networks at refineries. “The ability to image over a wide area and see these leaks is vital,” said Malcolm. “We can look at hydrocarbons and oils in a number of different scenarios at a range of sensitivity levels.” The next focus for the company is to extend the range of the Firefly beyond 5 microns. One competitor in this space is the quantum cascade laser but Malcolm is confident that an upgraded Firefly would have better tunability as well as better peak and average powers. “We are making progress, and getting there fast,” he said.
About the Author
Jacqueline Hewett is a freelance science and technology journalist based in Bristol, UK.

Video: stand-off imaging of methane gas with M Squared’s Firefly source tuned to the molecule’s 3.35 micron absorption line.

Probes Promise Precise On-Wafer Measurements At THz Frequencies

2012-02-16T18:06:00.000-08:00

Image via Wikipedia

Terahertz-frequency integrated circuits (ICs) offer tremendous promise in terms of available bandwidth for short-range communications. Although such devices have been fabricated for use at frequencies through 3000 GHz (3 THz), the on-wafer commercial probes for characterizing these high-frequency ICs are limited to about 340 GHz. As a solution, Theodore J. Reck, Lihan Chen, Chunhu Zhang, Alex Arsenovic, Christopher Groppi, Arthur W. Lichtenberger, Robert M. Weikle II, and N. Scott Barker—who combined their talents from the University of Virginia and Arizona State University—have presented a scalable approach to the fabrication of high-frequency wafer probes that integrates a rectangular-waveguide probe and coplanar-waveguide (CPW) wafer probe onto a single silicon chip. The wafer probes feature a ground-signal-ground (GSG) configuration on a 15-micron-thick silicon substrate.
The experimental probe consists of an E-plane split waveguide block that houses the silicon chip. Tabs of silicon electroplated with gold are clamped between the two halves of the block, both for mechanical support and alignment of the housing. The probe chip couples from rectangular waveguide through a radial E-plane waveguide probe into a transmission-line channel. This channel emerges from the block where the signal mode is converted to the GSG wafer probe.
To verify that the design was capable of providing sufficient force to achieve a low-resistance contact with an IC under test, a probe with a single tip was fabricated and evaluated with different contact forces. A contact resistance of 0.07 Ω was achieved for a contact force of 1 mN. See “Micromachined Probes for Submillimeter-Wave On-Wafer Measurements—Part 1: Mechanical Design and Characterization” and “Part 2: RF Design and Characterization,” IEEE Transactions on Terahertz Science and Technology, November 2011, pp. 349 and 357.