Graphene contact lens allow infrared vision after a breakthrough by University of Michigan researchers. Graphene has been around for a few years now, and the idea of using it detect infrared radiation is nothing new, but there were hurdles to be cleared in developing the contact lens. The new lens feature two layers of graphene with an insulating layer sandwiched in between. Because the sheets are so thin they are ideal for integration into a contact lens, cell phones, and other electronics, but the drawback is that the layers are so thin they only capture a little more than two percent of the light energy that strikes them. The signal generated by this is about a thousand times too weak to be utilized by imaging systems we have today, but clever design makes the new lens to obvious choice for the future.
The researchers solved the problem of the weak signal by running a mild electric current through the bottom layer of graphene. As light strikes the top layer, the photons cause small areas to become positively charged, and the electrons reach the bottom layer of graphene through the insulator as a result of the quantum tunnelling effect. As the charge in the top layer fluctuates due to the incoming light electrons, the current running through the bottom layer changes significantly enough to be measured, allowing the researchers to harvest the signals needed to create an image from the graphene sheets on a connected display.
The resulting graphene contact lens is of course very thin, and can detect light in the near infrared spectrum as well as current detectors on the market, but without the bulky cooling equipment that causes older devices to large and cumbersome. Currently detecting mid and far infrared radiation requires the use of cooling outright, and detecting the different wavelengths in one device requires a combination of different technologies to pick up each wavelength individually. While the new graphene contact lens allow infrared vision in just the near field spectrum, it is it is very impressive in a device small enough to fit in a contact lens, and it is likely that future revisions will refine the detection technology and allow a broader use of the spectrum.
The lens will also feature a built-in camera, and as bionic technology improves, it is likely that a similar device will one day allow for people to have infrared and ultraviolet light detection based vision connected directly to their brain. The graphene sheets currently detect the entire spectrum of visible light, near infrared is an added bonus. The ultimate goal for the researchers of these lens is a device that allows people to shift between spectrums as they wish, navigating by infrared when it is too dark to see normally, then switching back to the visible spectrum when it is available. Although a device with those capabilities is many years down the road, these new graphene contact lens that allow infrared vision are an extremely impressive first step.
By Daniel O’Brien