In the News

28 April 2005

IQE MATERIAL USED BY NASA TO BUILD FOUR COLOUR IR CAMERA


As reported in CompoundSemiconductor.Net this month, NASA builds first four-color infrared camera.

Advanced Epitaxial Quantum Well Infrared Photodetector materials produced by IQE have been employed by researchers at NASA's Jet Propulsion Laboratory, Pasadena, Ca., to create the world's first four-band infrared focal camera that will allow them to "see" details in infrared that were unachievable with previous technology.
The human eye cannot detect infrared light which is essentially the heat emitted by every object whose temperature is above absolute zero.

This new technology provides researchers with a wider view in the field of remote sensing for pollution detection, weather prediction and a host of other vital atmospheric and geological applications on Earth. It will assist with monitoring crop health, tropical rainforest deforestation and industrial pollutants.

"This technology will revolutionize the way we develop new remote sensing instruments," said team leader Dr. Sarath Gunapala, senior research scientist at JPL. "One such example is the detection of smog. Smog contains a range of chemicals, which only appear in certain infrared ranges. The multi-band capacity of the camera array will allow researchers a full spectral view to identify them."

IQE manufactured the quantum well materials by “growing” stacks of very thin but precise materials with layers as thin as a few atoms (as specified by the JPL device design) . When light from the infrared part of the electromagnetic spectrum strikes the material, trapped “carriers” in the quantum wells are photo-ionised and swept away by an externally applied electronic field, producing a photocurrent.

The new four-band Quantum Well Infrared Photodetector camera can see up to 15.5 microns, or 15 one-millionths of a meter in the infrared. Its focal plane can be compared to the retina of an eye. More nerve endings on a retina provide more detailed sight. Thus, adding more pixels to the bands increases the detail and information the camera can capture. Each band, or focal plane, measures 128 by 640 pixels.

The existing one-band technology Quantum Well Infrared Photodetector technology developed at JPL has been licensed for various commercial applications, including non-invasive detection of breast and skin cancers. The camera has also proven useful to firefighters and television news helicopter crews by allowing them to see forest fire hot spots through heavy smoke.

Drew Nelson, IQE’s Chief Executive Officer said: “IQE has, over many years, established a close working relationship with NASA’s Jet Propulsion Laboratories for new and highly advanced electronic and optical materials and has demonstrated technical leadership along with the ability to consistently meet the stringent requirements necessary for the development of leading edge technologies.”
 

The camera has already flown over and imaged parts of Africa as part of an international project to study the environmental impact of vegetation burning and related ecological effects. Ultimately, this detector will form the basis for a hyperspectral infrared imaging instrument (perhaps upwards of 64 bands) as part of a collaboration between JPL, NASA's Goddard Space Flight Center, Greenbelt, Md., and U.S. Army Research Laboratory, Adelphi, Md.
 

Dr Gunapala added; "As a result of all our research work in last decade, QWIP technology has culminated as the most favorable highly sensitive multi-band large format focal plane array technology in long-wavelength infrared region. Currently, JPL and IQE are jointly developing large multi-band QWIP imaging focal plane arrays on 6-inch GaAs wafers using highly mature GaAs growth and processing technologies. In future end users can expect the cost of large area multi-band imaging arrays to be lowered significantly as consequence of this large area growth and processing capability of QWIPs."
 

JPL is managed for NASA by the California Institute of Technology in Pasadena.


 

For the original article, visit the CompoundSemiconductor.Net website:

Contact:

Chris Meadows, IQE plc

+44 (0) 29 2083 9400