University of Michigan researchers have developed an infrared sensor that can be inserted into a contact lens.
“We can make the entire design super-thin,” said Zhaohui Zhong, an assistant professor of electrical engineering and computer science, in a university press release. "It can be stacked on a contact lens or integrated with a cell phone. "
The sensor doesn't require bulky cooling equipment. Instead it uses graphene - a single layer of carbon atoms - which can sense visible and ultraviolet light. But until now, graphene hasn’t been viable for infrared detection because it can’t capture enough light to generate a detectable electrical signal, said Univ. of Michigan.
So, researchers used a different approach. Rather than trying to directly measure the electrons that are freed when light hits the graphene, they amplified the signal by looking instead at how the light-induced electrical charges in the graphene affect a nearby current.
By measuring the change in current, the team could deduce the brightness of the light hitting the graphene," the university said. "The new approach allowed the sensitivity of a room-temperature graphene device to compete with that of cooled mid-infrared detectors for the first time."