High-performance infrared cameras are crucial for civilian and military applications such as night-vision goggles and search-and-rescue operations. Existing cameras usually fall into one of two types: active cameras, which use an invisible infrared source to illuminate the scene, usually in the near or short-wavelength infrared; and passive cameras, which detect the thermal radiation given off by a warm object, typically in the mid- or long-wavelength infrared, without the need for any illumination. Both camera types have advantages and disadvantages in the field.
Integrating both modes of imaging into a single camera would open new possibilities — but doing so has proven challenging. Until now, dual-mode active and passive infrared cameras needed either two different infrared detectors or complex controllable filters to accommodate the different wavelengths, and then required additional signal processing to reconstruct a single image from the two modes.
However, in a move that may change the way we look a two-color imaging, researchers at the Northwestern University's Center for Quantum Devices have now found a way to integrate active and passive infrared imaging capability into a single chip. This opens the way to lighter and simpler dual-mode active/passive cameras with lower power dissipation.
A paper about the findings, "Active and Passive Infrared Imager Based on Short-Wave and Mid-Wave Type-II Superlattice Dual-Band Detectors," was published January 1 in the journal Optics Letters. The work was led by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science in Northwestern's McCormick School of Engineering and Applied Science.
The researchers achieved this feat by engineering the quantum properties of novel semiconductor materials called the indium arsenide/gallium antimonide (InAs/GaSb) type-II superlattices. Researchers at the center have been pioneering the development of type-II superlattices as a superior replacement of aging mercury-cadmium-telluride (HgCdTe) infrared camera technology in terms of both performance and cost.
Using the unique band-structure engineering capabilities of type-II superlattices, they have developed a new structure incorporating two different superlattices with different layer spacings, thus enabling detection with a cutoff wavelength of either 2.2µm (active mode) or 4.5µm (passive mode). This new device can simply switch from passive to active mode by a very small change in bias.
Northwestern University: http://www.northwestern.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Drones are being used to capture video footage that shows construction progress at the Sacramento Kings’ new stadium in California.
It’s becoming increasingly difficult to keep track of online reading material. That’s why physical print-outs sometimes trump a digital copies
Websites try to suggest everything from your next best friend to your next best shirt. But are these recommendations a help or a hindrance?
A new app called Infltr taps into a smartphone's graphics processor to generate filters on the fly, allowing for the perfect shot in one step
Windows 95, the operating system update that changed the way millions of people interacted with their computers, was released 20 years ago today.
Atmospheric CO2 can be turned into carbon nanofibres for high-tech uses a method that may also hold promise for profitable carbon capture
Atlas, a humanoid robot, can run on natural terrains such as soil and rocks. Here it is seen navigating through woodland and jogging along a nature trail. This promotional film from Atlas’s maker Boston Dynamics, owned by Google’s parent company Alphabet, is narrated by company founder Marc Railbert and formed part of the FAB 11 conference at the Massachusetts Institute of Technology
Investors see riches in a cryptography-enabled technology called smart contracts–but it could also offer much to criminals.
A California automotive start-up is hoping their prototype supercar will redefine car manufacturing. The sleek race car dubbed 'Blade' didn't come off an assembly line - but out of a 3D printer.
Technology could create -- or stop -- a disaster in the sky