Abstract-GaP based terahertz time-domain spectrometer optimized for the 5-8 THz range

http://apl.aip.org/resource/1/applab/v101/i18/p181101_s1?bypassSSO=1

I. D. Vugmeyster,1 J. F. Whitaker², and R. Merlin¹

Department of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120, USA
²Center for Ultrafast Optical Science, The University of Michigan, Ann Arbor, Michigan 48109-2099, USA 

We use GaP to generate terahertz pulses via optical rectification in a collinear phase-matched configuration relying on the dispersion of the refractive index. The GaP-based time-domain system operates up to 8 THz and is especially well suited at high frequencies, where it has high signal-to-noise ratio and power conversion efficiency ∼30 times greater than those of commercial photoconductive emitters. These characteristics are demonstrated in measurements of ZnTe in the reflection geometry. We also discuss the power output and describe theoretically the observed THz field generation by nonlinear mixing, the field's free space propagation, and its detection.

Abstract-Threshold of Terahertz Population Inversion and Negative Dynamic Conductivity in Graphene Under Pulse Photoexcitation

 http://arxiv.org/abs/1210.6704

We theoretically study the population inversion and negative dynamic conductivity in intrinsic graphene in the terahertz (THz) frequency range upon pulse photoexcitation with near-/mid-infrared wavelength. The threshold pulse energy required for the population inversion and negative dynamic conductivity can be orders-of-magnitude lower when the pulse photon energy is lower, due to the inverse proportionality of the photoexcited carrier concentration to the pulse photon energy and to the weaker carrier heating. We also investigate the dependence of the dynamic conductivity on the momentum relaxation time. The negative dynamic conductivity takes place either in high- or low-quality graphene, where the Drude absorption by carriers in the THz frequency is weak.

Abstract-Terahertz generation using plasmonic photoconductive gratings

Christopher W Berry and Mona Jarrahi

http://iopscience.iop.org/1367-2630/14/10/105029

A photoconductive terahertz emitter based on plasmonic contact electrode gratings is presented and experimentally demonstrated. The nanoscale grating enables ultrafast and high quantum efficiency operation simultaneously, by reducing the photo-generated carrier transport path to the photoconductor contact electrodes. The presented photoconductor eliminates the need for a short-carrier lifetime semiconductor, which limits the efficiency of conventional photoconductive terahertz emitters. Additionally, the photo-absorbing active area of the plasmonic photoconductive terahertz emitter can be increased without a significant increase in the capacitive loading to the terahertz radiating antenna, enabling high quantum-efficiency operation at high pump power levels by preventing the carrier screening effect and thermal breakdown. A plasmonic photoconductive terahertz emitter prototype based on the presented scheme is implemented and integrated with dipole antenna arrays on a semi-insulating In_0.53Ga_0.47As substrate. Emitted terahertz radiation is characterized in a terahertz time-domain spectroscopy setup, measuring a terahertz pulse width of 590 fs full-width at half maximum in response to 150 fs pump pulses at 925 nm.

Agilent Technologies and the University of Leeds Open Terahertz Measurement Research Lab

http://www.sys-con.com/node/2421446

Agilent Technologies Inc. (NYSE: A) today announced the opening, at the University of Leeds, of the first Agilent-equipped terahertz measurement laboratory in Europe. The new laboratory will enable research on devices, components, circuits and systems at much higher frequencies than any other institution in the region has been able to do before.

The lab is set up in memory of professor Roger Pollard, former dean of engineering at the University of Leeds and a long-time friend of Agilent, who passed away at the end of last year. The Agilent 1.1-THz PNA network analyzer is the centrepiece of the new lab.

Peter Jimack, dean of engineering at the university, and Greg Peters, general manager of Agilent’s component test division, formally opened the laboratory. Featured guest speaker professor Giles Davies delivered a keynote presentation on terahertz technology.

“Roger Pollard had a long history of collaboration with Agilent, spanning more than 30 years, and held the Agilent Technologies chair in high-frequency measurements,” said professor Peter Jimack. “We are extremely grateful to Agilent for its continued support and, in particular, for the generous sponsorship of this exceptionally well-equipped laboratory in recognition of Roger’s contribution to Agilent’s success.”

The PNA THz network analyser supports a broad range of projects in nanoelectronics, complemented by a new electron-beam lithography facility. In the new field of graphene, the network analyser will allow the university staff to perform on-wafer terahertz measurements of transistors, THz biosensors, magnetic storage elements, THz spin-switches and novel acoustoelectric devices. It will also be used to characterise THz passive components such as filters, waveguides, fibres and antennas.

“This laboratory is a fitting tribute to Roger,” said Graham Newton, district manager, UK, for Agilent’s Electronic Measurement Group, “both in terms of providing a location for cutting-edge research as well as reflecting the close relationship Roger had with us over so many years.”

“Roger’s technical brilliance contributed to many innovations in network analyzers, calibration, and measurement science that Agilent brought to the marketplace,” said Henri Komrij, business manager, Component Test Division, Agilent. “His leadership abilities motivated engineers to be more creative, collaborative and innovative. Roger absolutely loved development – of engineering and people. A high-frequency lab named for Dr. Pollard at Leeds, an esteemed university, is a truly appropriate honor for a well-regarded colleague.”

About the University of Leeds School of Electronic and Electrical Engineering

The School of Electronic and Electrical Engineering is the top electronic and electrical engineering department in the UK, as determined by the 2008 Research Assessment Exercise, which rated an impressive 80 percent of its research activity as internationally excellent or world-leading. The Institute of Microwaves and Photonics has an outstanding pedigree in microwave engineering research going back 50 years and is recognized as one of the very best centers for terahertz electronics and photonics in the world. The faculty of engineering at the University of Leeds is ranked seventh in the UK for the quality of its research (2008 Research Assessment Exercise); an impressive 75 percent of the faculty’s research activity rated as internationally excellent or world-leading.

Institute of Microwaves and Photonics, University of Leeds

The Institute of Microwaves and Photonics has an outstanding international reputation with a pedigree dating back to 1963. The institute has an extensive research program in the area of microwave, millimetre-wave and terahertz devices, circuits and systems as well as in quantum electronics and bio-nanoelectronics. The institute has excellent microwave and millimetre-wave design, fabrication and measurement facilities including network analysis up to 1.1 THz, a class-100 clean room, MBE growth and a new electron-beam lithography facility.

About Agilent Technologies

Agilent Technologies Inc. (NYSE: A) is the world’s premier measurement company and a technology leader in chemical analysis, life sciences, diagnostics, electronics and communications. The company’s 20,000 employees serve customers in more than 100 countries. Agilent had net revenues of $6.6 billion in fiscal 2011. Information about Agilent is available at www.agilent.com.

Checking in on TeraTop

TeraTOP

Terahertz Photonic Imager on Chip

My Note: I try to keep an eye on developments at TeraTop,  by checking their webpage intermittently. The last news article posted references a project meeting to be held last February, but  nothing has been posted since then (which is accessible to the public at least). The lofty goals of TeraTop,  are identified on the webpage below.
 I note that Darpa, is also working in this area, and is getting closer to the development of a solid state THz chip operating at frequencies above 1 THz, and it will be interesting to see if TeraTop can reach the 1.5 THz range by project close in 2014.  
http://www.teratop.eu/node/1

The impressive developments in the field of electronic imaging based on CMOS Imagers have generated worldwide enormous business opportunities, with revenues of more than $4B in 2009 at the component level alone. Today such Imagers almost solely address the visible and near-infrared part of the electromagnetic spectrum. Many applications would profit from affordable and reliable Imagers for the terahertz band, notably in surveillance and security.
The goal of TeraTOP is to develop a new high performance, low cost, THz Imager for passive imaging systems (0.5-1.5THz) based on CMOS batch manufacturing processes: A unique combination of several leading technologies will enable a real quantum leap in THz Imaging in terms of performance, size and costs. THz photonics components (THz lens, optical window and filters), THz antennas, CMOS-SOI (Silicon on Insulator) and NEMS are the key enabling building blocks that will be developed and combined to achieve such a breakthrough in functionality (passive, room temperature operation), performance (NETD of 0.5K), component size (THz imager on a chip) and significant cost reduction (< 7000 €).
The objective is to bring the disruptive technology from the research lab closer to applications, by developing a passive THz Imager for Concealed Weapons Detection. The cost efficient approach will enable a massive deployment of the TeraTOP Imagers, including crowded places, providing therefore a highly efficient response to terrorists' threats. Other applications can be envisioned in medical imaging e.g. skin cancer detection, or astronomy.
The consortium includes a mix of scientific and technological excellence (University of Wuppertal, the IIT, CEA-Léti), as well as leading industrial research groups (IBM, CSEM) and companies (EADS, QMC). The exploitation activities will be led by the key European industrial partner EADS. This will ensure that the project will target the current security needs and the results will lead to product development and promptly implemented on a wide scale across Europe for the benefit of its citizens.

Abstract-Active control of electromagnetically induced transparency analogue in terahertz metamaterials

http://www.nature.com/ncomms/journal/v3/n10/full/ncomms2153.html

Jianqiang Gu, Ranjan Singh, Xiaojun Liu, Xueqian Zhang, Yingfang Ma,, Shuang Zhang,  Stefan A. Maier, Zhen Tian, Abul K. Azad,, Hou-Tong Chen,Antoinette J. Taylor,Jiaguang Han, Weili Zhang

Recently reported metamaterial analogues of electromagnetically induced transparency enable a unique route to endow classical optical structures with aspects of quantum optical systems. This method opens up many fascinating prospects on novel optical components, such as slow light units, highly sensitive sensors and nonlinear devices. In particular, optical control of electromagnetically induced transparency in metamaterials promises essential application opportunities in optical networks and terahertz communications. Here we present active optical control of metamaterial-induced transparency through active tuning of the dark mode. By integrating photoconductive silicon into the metamaterial unit cell, a giant switching of the transparency window occurs under excitation of ultrafast optical pulses, allowing for an optically tunable group delay of the terahertz light. This work opens up the possibility for designing novel chip-scale ultrafast devices that would find utility in optical buffering and terahertz active filtering

TeTechS Inc., is developing a novel terahertz (THz) sensor system

http://www.cmc.ca/en/AboutCMC/SuccessStories/EnergyEnviro/TerahertzBenefitingEnvironmentTeTechS.aspx

Founded by Dr. Daryoosh Saeedkia (pictured), TeTechS Inc. draws on the distinctive characteristics of leading-edge terahertz technology to develop unique sensing and imaging solutions. The company’s systems can precisely identify and quantify materials in mixtures and composites by resolving their unique terahertz spectral signatures and fingerprints. Customers’ problems can be solved in ways that cannot be addressed by other approaches such as X-ray and infrared imaging.


Dr. Daryoosh Saeedkia’s startup company, TeTechS Inc., is developing a novel terahertz (THz) sensor system that can identify different types of plastics. It will offer an automatic way for recycling plants to separate the dark plastics used in computers, televisions, cell phones and other electronic devices, according to Saeedkia. The system will allow selected types of recycled plastics to be sold to manufacturers— and keep the material out of landfill. That’s where much of it now ends up when people get rid of their old electronics

“Currently, there is a mixture of plastics coming     

from the recycling stream. As a mixture, it has

quite a low value for building new products,”

Saeedkia explains. “Value is enhanced when we

are able to separate the mix of plastics according

to polymer type, so that the most appropriate

material can be sold to a manufacturer who will

use it to build a case for a computer or television

set. So the value goes up and the recycling loop

is closed.”

The terahertz band is the wavelength range that

falls between microwave and infrared on the

electromagnetic spectrum. Many materials,

including different types of plastics, have spectral

fingerprints in the THz range. This means that

THz spectroscopy can be used to distinguish

between them. “Materials exhibit unique qualities

when observed in the terahertz band that one can

harness to perform tasks that might not be easy

or even possible to do with
other technologies,” says
Saeedkia.

Saeedkia founded TeTechS
in 2010 and serves as its
President and CEO. He is
invigorated by opportunities
to develop disruptive
innovation using the unique
properties of terahertz
technology and to deliver
new products to market.
Based in Waterloo, the
company presently has four
full-time employees and is
bootstrap financing this stage
of operations. Previously,
Saeedkia served as the
chief technology officer of
T-Ray Science Inc., now
Verisante (VRS.VN: TSX-V),
which manufactures medical
devices.
Saeedkia began working
on a terahertz sensor as
a graduate student at the
University of Waterloo,
where he received his
doctorate degree in 2005
and subsequently was the
coordinator of the university’s
Microwave and Terahertz
Photonics Integrated System Lab (MISL). He
says CMC Microsystems gave him a boost in
the early stages of the work and helped with
the fabrication requirements. “We built our very
first THz chips with outstanding performance
through CMC Microsystems. They helped us
get going. It was a great honour and a big help.
Getting recognition from institutions like CMC
is confirmation that you are on track. It helps
you gain confidence.” In 2008, Saeedkia won
CMC’s Douglas R. Colton Medal for Research
Excellence in recognition of his research on
terahertz photoconductive sources, detectors
and terahertz photonics devices and systems.
Terahertz sensor systems that will be deployed
in an industrial setting have to be rugged. They
also have to be able to do material sensing
in real time. The proprietary terahertz sensor
technology developed by TeTechS takes
advantage of an all-optical-fiber laser light
delivery system in a compact and regularized
system architecture. These terahertz

sensors are fabricated on a multi-quantum well
InGaAs material system suitable to operate at
telecommunication wavelengths.
The material system was developed through
a two-year research collaboration between
TeTechS and the University of Manchester, UK.
The THz sensors are packaged in compact fiber
pigtailed chip enclosures. A laser light is delivered
to the sensors through optical fibers.
The company’s products are being developed
with support from a number of federal and
provincial agencies. Through discussions with
several potential customers and partners in the
recycling industry, Saeedkia is building interest
in his company’s technology. He also sees
an opportunity to market terahertz sensors to
industrial research teams working in other sectors
or to universities or research centres. “There
are R&D groups that want to buy an off-the shelf
sensor such as TeTechS is developing/

Financial ace quits Taptu for TeraView

http://www.businessweekly.co.uk/hi-tech/14695-financial-ace-quits-taptu-for-teraview

Thursday, 25 October 2012 10:53 TONY QUESTED

FINANCIAL ACE QUITS TAPTU FOR TERAVIEW

TeraView, the Cambridge UK pioneer in terahertz solutions and technology, has appointed a new chief financial officer as it steps up its global growth strategy.

Lynsey Wilson is a senior level finance executive with over 15 years finance and accounting experience focused on the management of technology-based SME’s.

She joins Teraview from Taptu, where as CFO she was involved in the sale of the company to RSS ad giant Mediafed.

Bruce Anderson, the current chief financial officer, is staying on with TeraView as a senior adviser.

Dr Don Arnone, TeraView CEO said: “Lynsey’s extensive financial experience across a number of innovative technology companies will clearly enhance TeraView’s management team.

“We are excited to welcome Lynsey and she will be a great asset to our future growth strategy. We also wish to take this opportunity to thank Bruce for his commitment to the company and his substantial contribution to its commercial progress over the past several years.”

TeraView was recently cleared by regulators to start trials of a world-first, hand-held breast cancer probe. With support from the Technology Strategy Board (TSB) and in collaboration with surgeons at Guy’s Hospital in London, TeraView has developed the device as part of the world’s first commercial terahertz medical unit.

In January, the company secured $5.5m of investment from a consortium of US, Asian and EU based institutional and corporate investors.

TeraView markets itself as the world’s first company devoted to the application of Terahertz light for spectroscopy and imaging. A spin out from Toshiba and Cambridge University in 2001 and employing circa 25 staff, TeraView has been developing the technology across a number of areas and applications and now has equipment in over 20 countries.

Headquartered in Cambridge, TeraView offers sales and support throughout Europe, North America and the Far East either directly or through a network of distributors.

• PHOTOGRAPH SHOWS: Dr Don Arnone

Anteral presents its new encapsulated Terahertz sensor TSW-90 in W-band

ANTERALInnovative Antenna and Terahertz Imaging Technologies

http://www.anteral.com/news/anteral/TSW-90_sensor

Submitted by anteral on Fri, 26/10/2012 - 13:13

Anteral presents its new encapsulated Terahertz sensor TSW-90 in W-band, with a range of operation from 80 to 100 GHz. This sensor output provides a DC voltage proportional to the power received in the working band.

Image: The front interface of the TSW-90 sensor.

This direct detection sensor includes an LNA before the detector, giving it an extraordinary sensitivity that allows it to be used even for passive applications without the need for a THz illumination source.

The module includes a front WR-10 waveguide interface, and an SMA connector signal output and 5V supply in its back, simplifying the interconnection with other systems.

Current Computed Tomography and Terahertz Efforts at NASA Glenn Research Center

October 30, 2012 2:30PM to 3:30PM

Presenter: 

Don J. Roth, NASA Glenn Research Center

Location: 

Building 208, Room C234

Type: 

Seminar

Series: 

Nuclear Engineering Division Seminar

Abstract:
This talk covers recent technical efforts in the X-ray micro-computed tomography (uCT) and terahertz areas at NASA Glenn Research Center. The first part of the talk will discuss the uCT work being done for the Advanced Stirling Radioisotope Generator program in which NASA is partnering with DOE, Lockheed-Martin, and Sunpower Corp. The focus of this program is to develop an ultra high efficiency, lower mass Stirling convertor for use with a radioisotope, reactor, or solar concentrator heat source for power on beyond-earth-orbit space missions. A high resolution micro-CT system has been assembled and is being used to provide optimal characterization for ultra-thin wall space components in this program.

This talk will discuss many aspects of the development of the CT scanning for this type of component, including CT system overview; inspection requirements; process development, software utilized and developed to visualize, process, and analyze results; calibration sample development; results on actual samples; correlation with optical/SEM characterization; CT modeling; and development of automatic flaw recognition software. In the second part of the talk, the assembly of a terahertz system and its use in computed tomography and reflection modes for NASA thermal and environmental protection system materials will be briefly described. The THz tomography system can inspect samples as large as 0.0283 m3 (1 ft3) with no safety concerns as for x-ray computed tomography. The reflection mode THz capability is being investigated for use in simultaneously characterizing thickness and microstructural quality in coatings with the same set of measurements.