Featured Research

from universities, journals, and other organizations

Perfect Night Vision? New Superlattice Structure Enables High Performance Infrared Imaging

Date:
June 1, 2008
Source:
Northwestern University
Summary:
Scientists 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. The technology has the potential for broad applications in the detection of terrorist activities, such as use in night vision, target identification, and missile tracking.

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.


Story Source:

The above story is based on materials provided by Northwestern University. Note: Materials may be edited for content and length.


Cite This Page:

Northwestern University. "Perfect Night Vision? New Superlattice Structure Enables High Performance Infrared Imaging." ScienceDaily. ScienceDaily, 1 June 2008. <www.sciencedaily.com/releases/2008/05/080528095919.htm>.
Northwestern University. (2008, June 1). Perfect Night Vision? New Superlattice Structure Enables High Performance Infrared Imaging. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2008/05/080528095919.htm
Northwestern University. "Perfect Night Vision? New Superlattice Structure Enables High Performance Infrared Imaging." ScienceDaily. www.sciencedaily.com/releases/2008/05/080528095919.htm (accessed September 20, 2014).

Share This



More Matter & Energy News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins