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 Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa

nachricht Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik

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: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>