COMING SOON: A NEW GENERATION OF INFRARED SENSORS
To help detect everything from enemy missiles to embryonic human tumors, a new generation of infrared light sensors is being tested at the University of Illinois at Chicago's Microphysics Laboratory.
Funded by approximately $3.9 million from the U.S. Department of Defense and NASA, researchers at UIC will study the properties of a promising semiconductor material called mercury cadmium telluride, which may be used in a variety of applications ranging from the military to medicine.
Mercury cadmium telluride-a compound semiconductor that exhibits superior abilities over simpler, more commonly used semiconductors-could improve the detection of various wavelengths of heat-producing infrared light. Creating useable crystals of this semiconductor, however, took a bit of laboratory magic.
"We've grown almost perfect crystals," said Inder Batra, professor and head of physics. "It's technologically complex to grow this material without creating defects, which would destroy any possibility of useful application in infrared detectors."
Using sophisticated devices called molecular beam epitaxial systems, UIC researchers continue to work on refining the semiconductor crystals to make them both better and cheaper. Their work for the DOD, funded by a five-year, $2.6 million grant, will concentrate on further improving the mercury cadmium telluride-the third most important semiconductor after silicon and gallium arsenide in terms of governmental and industrial research investment dollars.
In other testing for NASA, a $1.3 million contract will allow the researchers to closely examine how to develop infrared sensors to detect longer, and hence colder, wavelengths of infrared light. Expected to serve as the centerpiece of the testing is nanotechnology-the building of functional structures about the size of atoms.
One of the many challenges the researchers face is finding a way to make sensors that operate in so-called room-temperature environments, "and still meet the more stringent wavelength measurement requirements," said Christoph Grein, associate director of the laboratory. Such sensors, Grein said, may be used in future Mars probes, new infrared cameras, and on a new airborne-reflecting telescope to be mounted in a modified Boeing 747 aircraft.
While the Pentagon hopes better infrared detectors on surveillance satellites will improve the accuracy and speed of detecting enemy weapons and weapon-delivery systems, Siva Sivananthan, professor and director of the laboratory, also sees commercial benefits.
It's quite conceivable that sophisticated infrared night displays on car windshields will become commonplace as this technology improves and the price of the semiconductor drops, Sivananthan said. For example, sensors, mounted in automobile exhaust pipes, may be used to shoot and detect beams of infrared light through the outflowing gases. By analyzing the emission content, a message could be immediately sent back to the engine if a new fuel mix was needed for the car to run cleaner.
There are potential health benefits to infrared sensor research as well, Sivananthan said. "Using a combination of X-ray and infrared detection, at least one study suggests if we can put these technologies together, early detection of breast cancer could advance by about two years."
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