Researchers from the University of Science and Technology of China, Fudan University, and the University of Massachusetts Medical School say they’ve built contact lenses that let their wearer see in the infrared — no power source required, and even with their eyes closed.
“It’s totally clear-cut,” says senior author Tian Xue of the team’s creation. “Without the contact lenses, the subject cannot see anything, but when they put them on, they can clearly see the flickering of the infrared light. We also found that when the subject closes their eyes, they’re even better able to receive this flickering information, because near-infrared light penetrates the eyelid more effectively than visible light, so there is less interference from visible light.”
Researchers have developed contact lenses (top, middle) and goggles (bottom) that let you see in the infrared spectrum. (📷: Ma et al)
The lenses built by the team require no power source, working entirely passively to upconvert infrared light into visible light. To prove it, the team first tested the lenses on mice before placing them on human subjects — then asking them whether or not they could see signals emitted from an infrared LED, like the one used in remote controls.
Further development delivered a version of the lenses, which could convert different wavelengths of invisible infrared light into different wavelengths of visible light, letting wearers differentiate between 808nm, 980nm, and 1,532nm infrared light by converting them into green, blue, and red visible light respectively. This, the team suggests, could lead to lenses that assist with color blindness by converting certain wavelengths of visible light into other wavelengths.
The lenses are entirely passive, requiring no power source to operate — but the sensitivity of initial prototypes is low. (📷: Ma et al)
The only drawback: the image provided by the lenses is of a very low resolution. A wearable goggles version, built using the same technology, delivers a higher resolution by being positioned further away from the user’s retina — but in all cases the sensitivity was too low for the users to perceive any other sources of infrared radiation than a relatively strong LED.
The team’s work has been published in the journal Cell under open-access terms.