Optics breakthrough could improve infrared technology

"There are many applications that could greatly benefit from perfectly absorbing ultra-thin films," said researcher Björn Sturmberg.
By Brooks Hays  |  May 24, 2016 at 2:51 PM
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SYDNEY, May 24 (UPI) -- New research out of Australia promises to dramatically reduce the price of infrared technologies like night vision goggles.

Scientists at the University of Sydney recently demonstrated a semiconductor capable of a nearly 99 percent light absorption rate. The semiconductor is just a few hundred atoms thick and could power a range of infrared devices.

The semiconductors currently used in night and fog vision technologies absorb light at a rate of just 7.7 percent, which means a larger amount of the material is necessary to power infrared vision.

"Conventional absorbers add bulk and cost to the infrared detector as well as the need for continuous power to keep the temperature down," Martijn de Sterke, a physics professor at Sydney, said in a news release. "The ultrathin absorbers can reduce these drawbacks."

"By etching thin grooves in the film, the light is directed sideways and almost all of it is absorbed, despite the small amount of material -- the absorbing layer is less than 1/2000th the thickness of a human hair," de Sterke added.

The semiconductor doesn't rely on any special material, and the engraving technique could be used to boost the absorption of older infrared semiconductors.

"There are many applications that could greatly benefit from perfectly absorbing ultra-thin films, ranging from defence and autonomous farming robots to medical tools and consumer electronics," explained lead researcher Björn Sturmberg.

There are already thin light-absorbing films, but making and using them is time-consuming and expensive. They either involve complex production processes or the use of nanostructures, meta-materials and other exotic materials.

"There are major efficiency and sensitivity gains to be obtained from making photo-detectors with less material," Sturmberg said.

The new research was detailed in the journal Optica.

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