One day we may have everyday night vision goggles, thanks to an ultra-thin material that can capture infrared and visible light at the same time.
In a new study published on May 23 in Advanced Materialsresearchers in Australia have discovered that using “metasurface-based conversion technology”, you can create a night vision effect without the need for heavy light processing and cryogenic cooling components.
“These results promise significant opportunities for the surveillance, autonomous navigation, and biological imaging industries, among others,” lead investigator Dragomir Neshev from the Australian Research Council’s Center of Excellence for Transformative Meta-Optical Systems (TMOS), said in a STATEMENT. “Reducing the size, weight and power requirements of night vision technology is an example of how meta-optics and the work TMOS is doing is essential to Industry 4.0 and the future extreme miniaturization of technology.”
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Traditional night vision goggles operate by visible light or infrared photons passing through a lens to an electronic image intensifier tube consisting of a photocathode and a microchannel plate. The photocathode turns the photons into electrons, and these electrons then strike the microchannel plate, which has millions of holes that amplify their number. The electrons then interact with a phosphor-coated screen and emit a green glow, illuminating the scene the user is viewing.
The researchers explained that this current setup presents challenges due to its large size for a head-mounted device, thermal noise, and the inability to add infrared and visible images.
However, by using an “ultra-compact, high-quality lithium niobate resonant metasurface”—a very thin photonic device that can modulate the behavior of electromagnetic waves—the researchers increased the energy of the infrared photons, increasing their frequency to so as to bring their wavelengths within the visual spectrum.
Let there be visible light
Since infrared photons only pass through a single resonant metasurface and are then mixed with a pump beam—a light source used to amplify energy levels—night vision can be provided without the need to convert photons to electrons. This then bypasses the need for many heavy optical and cooling components to reduce thermal noise; upconversion from IR to visible light via the metasurface occurs at room temperature.
Additionally, this upconversion can capture both visible and invisible light in one image, which standard night vision systems cannot as they must display images from each spectrum side by side. This leads to non-identical images. As such, the researchers found that their approach provides live imaging and edge detection via infrared at the same time in a single view, increasing the overall quality of a night vision image.
This discovery has paved the way to smaller, thinner and more efficient night vision systems for a variety of applications, the scientists said. We could even see the advent of night vision goggles or filters that could be put over the goggles to help people see at night. Uses can range from helping to track a dog on an evening walk to making driving at night safer.