By harvesting the optical capabilities of graphene, researchers at the University of Michigan were able to create infrared contact lens morphed out of the carbon material.
Graphene is merely 1-atom thick that makes its absorb nearly 2.3% of light that strikes it, which of course is extremely less especially for generating an electric potential and hence makes it far away from operating as an infrared sensor. Therefore, the researchers devised an innovative technique to resolve this issue. In place of gauging lost electrons by incoming light, they augmented the current near the electrical signals created by the light upon hitting.
Augmentation was achieved by sandwiching a layer of insulator between two thin sheets of graphene. Flow of electricity was passed through the lower sheet. When light is made to strike on the top layer, the electrons are freed leaving behind the positively charged electron holes.
Free electrons then burrow through the insulating barrier causing the tunneling effect. While the remaining electron holes create an electric field that influences the current flowing through the lower sheet. By gauging the variation in electric current in lower layer, the researchers derived the amount of light that must be introduced on the top sheet.
Sensitivity of the resultant device achieved at room temperature is equivalent to the cooled mid-infrared detectors. And the team behind the study has already fabricated a standard contact lens sized infrared sensors. Integrating it with regular contact lens would augment the overall vision said Zhong, one of the lead researcher behind the study.
As expected the technology may find its way into the military applications but the researchers envision it paving a way into the medical field as well, where it might assist doctors in monitoring the flow of blood.
Source: University of Michigan
Image: Institute of Physics