Scientists built night vision that shows full color instead of just green

Researchers at the Beijing Institute of Technology have unveiled a novel night vision device capable of producing full-color images from infrared light, marking a departure from the conventional monochromatic displays. Unlike traditional infrared imaging systems that translate light into a single color representing brightness, this innovative system maps varying wavelengths and intensities into distinct colors.

The key to this breakthrough lies in the use of mercury telluride quantum dots and a dual-layer OLED. Quantum dots, mere nanometers in size, exhibit discrete energy states and respond differently to incoming infrared light depending on its wavelength and intensity. This results in the generation of varying charge carriers. The dual-layer OLED structure, with one emitting red and the other cyan, offers an energy barrier that controls charge flow.

Lesser infrared input yields dim red light, while stronger or shifted wavelengths trigger more charge to cross the barrier, activating the cyan layer and resulting in a blend of colors and heightened brightness.

By directly translating the physics of the incoming infrared signal into color, rather than relying on a preset mapping, the device carries more information than its counterparts. The researchers envision this technology fostering the development of next-generation visual prosthetics.

However, the prototype eyeglass weighs 23 grams and is semi-transparent, allowing users to simultaneously see both the visible and infrared-enhanced images. In controlled experiments, the device successfully rendered clear, color-coded images of simple patterns and moving objects under shortwave infrared illumination. Additionally, the converted signal was found to trigger responses in engineered cells reacting to visible light, as well as induce measurable brain activity in mice and retinal responses in human volunteers when viewing infrared signals through the device.

Despite these promising results, certain limitations must be considered. The tests were conducted in controlled settings using simple, high-contrast targets, making it unclear how the system would perform in more complex, real-world scenarios. The OLED component necessitates external power, positioning the current version closer to a wearable display rather than a passive optical device.

Moreover, the mercury telluride used in the quantum dots is a heavy-metal compound, raising concerns about long-term safety and potential use in devices directly contacting the body.