A team of researchers from Australia's TMOS, the ARC Centre of Excellence for Transformative Meta-Optical Systems, has developed an ultralight infrared filter that could improve night vision technology.

According to the researchers, the filter is substantially thinner — even thinner than a piece of cling wrap — and could eventually be placed onto regular eyewear.

Artist's impression of non-linear infrared upconversion technology. Source: TMOSArtist's impression of non-linear infrared upconversion technology. Source: TMOS

Because most night vision goggles currently worn by military personnel and hunting enthusiasts tend to be large and bulky, they often avoid using the technology.
As such, the team developed the new ultra-light night vision filters, which weigh less than 1 gram, to enable users to glimpse both the visible and infrared spectrum. Additionally, the filters also allow users to drive safely in the dark.

Making it possible to reduce the footprint of this metasurface-based upconversion technology is that it requires fewer elements. The researchers noted that photons pass through a single resonant metasurface where they subsequently mix with a pump beam. Meanwhile, the resonant metasurface enhanced the energy of the photons, thereby drawing them into the visible light spectrum without the need to convert electrons as occurs with currently used technology. Further, this is also achievable at room temperature, thus eliminating the need for the bulky and heavy cooling systems also used in current technology.

“This is the first demonstration of high-resolution up-conversion imaging from 1550 nm infrared to visible 550 nm light in a non-local metasurface. We chose these wavelengths because 1550 nm, an infrared light, is commonly used for telecommunications, and 550 nm is visible light to which human eyes are highly sensitive. Future research will include expanding the range of wavelengths the device is sensitive to, aiming to obtain broadband IR imaging, as well as exploring image processing, including edge detection,” the researchers explained.

The researchers are eyeing the new filter for applications including surveillance, autonomous navigation and biological imaging industries, among others.

An article detailing the new filters, “Enhanced Infrared Vision by Nonlinear Up-Conversion in Nonlocal Metasurfaces,” appears in the journal Advanced Materials.

To contact the author of this article, email mdonlon@globalspec.com