Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Superlattice Structure Enables High Performance Infrared Imaging

30.05.2008
Scientists at the Center for Quantum Devices (CQD) in the McCormick School of Engineering at Northwestern University have demonstrated for the first time a high-performance infrared imager, based on a Type II superlattice, which looks at wavelengths 20 times longer than visible light.

Researchers at center, led by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science, say that such technology has the potential for broad applications in the detection of terrorist activities, such as use in night vision, target identification, and missile tracking.

Any object, including the human body, with a near-room temperature actively emits long wavelength (around 10 micron) infrared radiation (LWIR). Tracking this infrared radiation using high-speed infrared (IR) imagers would help to reveal thermal profiles of hidden targets or objects at night when no visible source is available. Such imagers also have potential use in medical applications where excessive heating or cooling in the body can indicate problems like inflammation, blood flow issues or even cancerous tissue.

In LWIR imaging applications, the dominant technologies are photodetectors based upon the HgCdTe (mercury cadmium telluride or MCT) material platform and the quantum well photoconductors (QWIP). Both of them have shown limitations that stimulated the research for alternative technologies. Type-II InAs/GaSb (indium arsenide/gallium antimonide) superlattices, first proposed by Nobel laureate Leo Esaki in 1973, became a potential for use in infrared detection in 1987. It wasn’t until semiconductor epitaxial growth techniques such as molecular beam epitaxy were sufficiently advanced in the 1990s that high-performance infrared photon detection based on these superlattices was fully demonstrated.

“The type-II superlattice will become the next generation infrared material replacing MCT technology,” says Razeghi. “MCT has many limitations, especially in the longer wavelength infrared range critical for missile detection.”

Razeghi’s research group has recently invented a new superlattice structure, called the M-structure, which boosted the performance of the type II superlattice to a new level. This new device structure is capable of detecting very low light intensity with high optical efficiency and exhibits an electrical noise level 10 times smaller than the original design. A LWIR 320x256 pixel focal plane array fabricated from this material has been able to differentiate temperature differences as low as 0.02 degrees Celsius. The camera was able to detect 74 percent of the incident photons, similar to other leading technologies.

Researchers recently presented their findings at the SPIE Photonics West Conference held in San Jose, CA on Jan. 19-24, 2008. This work was also published in the October 18, 2007 issue of the journal Applied Physics Letters.

The work performed at CQD has generated much interest in type-II superlattice research and has brought funding from the U.S. Missile Defense Agency, U.S. Air Force Research Laboratory, Office of Naval Research, and the Defense Advanced Research Projects Agency, as well as collaborations with Rockwell Scientific Company, Naval Research Laboratory, Airforce Research Laboratory, Jet Propulsion Laboratory, BAE, Lockheed, and Raytheon Company.

Kyle Delaney | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Physics and Astronomy:

nachricht Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich

nachricht Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>