Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Technology holds promise for infrared camera

12.08.2005


New technology developed at Northwestern University has the potential for broad application in the detection of terrorist activities such as missile attacks on U.S. troops. Scientists at the Center for Quantum Devices (CQD) have demonstrated, for the first time, uncooled infrared imaging using type-II superlattice technology. This significant development could lead to smaller, faster and less expensive hand-held infrared imaging devices.



High-speed infrared (IR) imagers are capable of sensing thermal profiles of missiles and other objects that emit heat above that of the background. These devices also have potential in medical applications where excessive heating or cooling in the body can indicate trouble, such as inflammation, circulation issues or even cancerous tissue.

"For most practical applications, high-speed operation with handheld portability is especially important," said CQD director Manijeh Razeghi, who led the research team. "Uncooled imagers are capable of handheld operation, which is critical in situations with soldiers on the battlefield or with firefighters in a smoke-filled environment. Cooled sensors, on the other hand, typically utilize liquid nitrogen for cooling to minus 200 degrees Celsius, making the sensors expensive and bulky."


Type-II superlattices were first proposed by Nobel laureate Leo Esaki in 1973 and were then proposed for use in infrared detection in 1977. It wasn’t until semiconductor epitaxial growth techniques such as molecular beam epitaxy were sufficiently advanced in the 1990s, however, that high-performance infrared photon detection was fully demonstrated.

Currently, silicon microbolometer sensors, which operate on a thermal response principle -- as opposed to photonic response -- are capable of operating at room temperature but are orders of magnitude slower than photon detectors. Photon detectors detect light at infrared wavelengths and convert it directly to an electrical signal, whereas thermal detectors are physically heated by the infrared signal, which changes the resistance of the detector element creating a varying electrical signal, and is a much slower process. Thus type-II superlattices, which are photon detectors, are far more suitable for many applications requiring high-speed operation, such as missile detection.

With a strong program in photonic III-V material growth, device fabrication and development, CQD researchers were the first to demonstrate an imaging type-II superlattice focal plane array, and were also the first to demonstrate uncooled photo detection using type-II superlattice structures.

Recently CQD researchers have demonstrated an uncooled 256 by 256 pixel camera using an InAs/GaSb type-II superlattice, which can detect variations in temperature on the surface of a hot soldering iron while operating at room temperature (with a cutoff wavelength of 5 microns).

"The type-II superlattice will become the next generation infrared material replacing mercury cadmium telluride, or MCT," said Razeghi, who is Walter P. Murphy Professor of Electrical and Computer Engineering. "MCT has many limitations, especially in the longer wavelength infrared range critical for missile detection, and we have demonstrated type-II detectors from three all the way up to 32 microns."

Razeghi’s research group has been in very active pursuit of uncooled infrared photon detection. In their work, the researchers fabricated the focal plane arrays using the superlattice materials grown with an Intevac Mod Gen II solid-source molecular beam epitaxy system. At room temperature, the detectivity (the unit of measure to compare detector performance) was around 109 cm·Hz1/2/W.

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 Defense Advanced Research Projects Agency, as well as collaborations with Rockwell Scientific Company, Naval Research Laboratory, Jet Propulsion Laboratory and Raytheon Company.

Megan Fellman | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Power and Electrical Engineering:

nachricht Silicon solar cell of ISFH yields 25% efficiency with passivating POLO contacts
08.12.2016 | Institut für Solarenergieforschung GmbH

nachricht Robot on demand: Mobile machining of aircraft components with high precision
06.12.2016 | Fraunhofer IFAM

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

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

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>