The first room-temperature light detector that can sense the full infrared spectrum has the potential to put heat vision technology into a contact lens. Unlike comparable mid- and far-infrared detectors currently on the market, the detector developed by University of Michigan engineering researchers doesn’t need bulky cooling equipment to work. Infrared vision may be best known for spotting people and animals in the dark and heat leaks in houses, but it can also help doctors monitor blood flow, identify chemicals in the environment and allow art historians to see Paul Gauguin’s sketches under layers of paint. Graphene, a single layer of carbon atoms, could sense the whole infrared spectrum — plus visible and ultraviolet light. But until now, it hasn’t been viable for infrared detection because it can’t capture enough light to generate a detectable electrical signal. With one-atom thickness, it only absorbs about 2.3 percent of the light that hits it. If the light can’t produce an electrical signal, graphene can’t be used as a sensor.
To overcome that hurdle, Zhong and Ted Norris, the Gerard A. Mourou Professor of Electrical Engineering and Computer Science, worked with graduate students to design a new way of generating the electrical signal.
“We can make the entire design super-thin,” said Zhaohui Zhong, assistant professor of electrical and computer engineering. “It can be stacked on a contact lens or integrated with a cell phone.”
“The challenge for the current generation of graphene-based detectors is that their sensitivity is typically very poor.”It’s a hundred to a thousand times lower than what a commercial device would require.” “Our work pioneered a new way to detect light“. “We envision that people will be able to adopt this same mechanism in other material and device platforms” Zhong said.
The device is already smaller than a pinky nail and is easily scaled down. Zhong suggests arrays of them as infrared cameras.