You know what would be cool? Being able to see in the dark. You know what’s decidedly less cool? Having to do so via clunky night vision goggles. Thanks to researchers out of the University of Michigan, streamlined, hands-free infrared vision may soon be within our grasp – they’ve created the first room-temperature light detector that can sense the full infrared spectrum, and it’s so thin it could fit on a contact lens.
The bulkiness for traditional infrared detectors comes from necessary cooling equipment, but scientists say this new design doesn’t need any of that.
“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.”
Infrared vision is famous for its use in police chases and military operations, but the applications aren’t limited to people with guns. Researchers say it can also help doctors monitor blood flow, identify chemicals in the environment and allow art historians to see original sketches from famous artists under layers of paint.
Graphene, a single layer of carbon atoms, has long been known to be capable of sensing the full spectrum of infrared light – it’s just that it’s been too thin to detect enough light to create a viable electrical sensor. That changed when they decided to add their own current to the device. Working with graduate students, the team decided to put an insulating layer between two graphene sheets. The bottom layer had a current running through it. When light hit the top layer, it freed electrons, creating positively charged holes. Then, the electrons used a quantum mechanical trick to slip through the barrier and into the bottom layer of graphene.
“Our work pioneered a new way to detect light,” Zhong said. “We envision that people will be able to adopt this same mechanism in other material and device platforms.”
The device, smaller than your little finger’s nail and easily scaled, is more or less ready application on things like contact lenses. The question, though, is how would humans respond to seeing in a different spectrum on a regular basis?