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IPFS News Link • Inventions

Night-vision lenses so thin and light that we can all see in the dark

•, By Bronwyn Thompson

This vision could be a reality, with a technology breakthrough that could deliver this elusive view to everyday consumers, with an ultra-thin film or lens the width of cling wrap.

Researchers from the ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS) in Australia have been on a quest to make night vision accessible and wearable, doing away with bulky and expensive headsets and lens attachments.

Their new findings allow all the complex light processing to take place along a simpler, narrower pathway, which essentially means the tech can be packaged up as a night-vision film that weighs less than a gram and can be placed across existing lensed frames.

Having an everyday pair of night-vision spectacles, that look much the same as reading or driving glasses, could change the way we work and play after dark. There's so much potential, from finding your off-leash dog in the park on a late-night walk, to enhanced safety behind the wheel and on foot.

So why aren't we already walking around with our night shades on? Traditional night vision involves a complex system that sees light photons pass through an objective lens, into an electronic image-intensifier tube made up of a two important parts. First, the photocathode converts photons into electrons, which then flow into the microchannel plate, made up of millions of holes to massively multiply electrons. Next, the electrons land on a phosphor-coated screen, and when they hit the phosphors, they 'glow' green, illuminating the scene being viewed through the night-vision system.

This method, understandably, would be impossible to currently squeeze onto an ultra-thin piece of plastic film.

Instead, TMOS researchers used metasurface-based upconversion technology, which essentially provides an easier pathway for light photons to be processed. The photons travel through a resonant metasurface, where they mingle with a pump beam. The non-local lithium niobate metasurface boosts the energy of the photons, and draws them into the visible light spectrum without the need to convert them to electrons first. It also doesn't require cryogenic cooling – which reduces 'noise' for sharper images in traditional night vision – so can do away with even more of the bulky night-vision goggle mechanics.