Tiny crystal films could make night vision an everyday reality

Not a strictly new technology but an improvement on existing concepts. This is building an artificial non-linear optic using a metamaterial to make it more compact. It works by frequency shifting the incoming infrared into the visible light spectrum without otherwise altering it. Of course it's just a proof of concept metamaterial so there's a bunch of practical limitations that will need to be overcome with engineering before it's ready for prime time.

The actual publication is at https://www.spiedigitallibrary.org/journals/advanced-photoni...

> Commercial infrared cameras convert infrared light to an electric signal, which is then shown on a display screen. They require low temperatures, because of the low energy and frequency of infrared light. This makes conventional infrared detectors bulky and heavy – some security personnel have reported chronic neck injury due to regular use of night vision goggles.

This isn't how military etc NVGs work; they use optics, and don't have active cooling. Eg, a photocathode made with gallium arsenide.

I liked this bit:

> The technology could be used in the agricultural industry to help monitor and maintain food quality control, and in remote sensing techniques such as LIDAR – a technology that is helping to map natural and manmade environments.

"Please give us some of your advertising money Google."

I hope they get the money they're asking for. It sounds like a really interesting experiment.

>"These technologies work by combining incoming infrared light with a strong light source – a laser beam – inside a material known as “nonlinear crystal”. The crystal then emits light in the visible spectrum.

However, nonlinear crystals are bulky and expensive, and can only detect light in a narrow band of infrared frequencies.

Metasurfaces provide the solution

Our work advances this all-optical approach. Instead of a non-linear crystal, we set out to use carefully designed layers of nanocrystal called “metasurfaces”. Metasurfaces are ultra-thin and ultra-light, and can be tweaked to manipulate the color or frequency of the light that passes through them.

This makes metasurfaces an attractive platform to convert infrared photons to the visible.

Importantly, transparent metasurfaces could enable infrared imaging and allow for normal vision at the same time.

Our group set out to demonstrate infrared imaging with metasurfaces. We designed a metasurface composed of hundreds of incredibly tiny crystal antennas made of the semiconductor gallium arsenide.

This metasurface was designed to amplify light by resonance at certain infrared frequencies, as well as the frequency of the laser and the visible light output. We then fabricated the metasurface and transferred it to a transparent glass, forming a layer of nanocrystals on a glass surface."

PDS: So, here's the next logical question then: If we have a metasurface, then what are its limits; it's extrema (min, max) -- in terms of wavelength conversion (AKA "use as a transducer") ?

Phrased another way, what are the max and minimum frequencies of waves that can be transduced from one type of wave to another?

Wouldn't it be interesting to do some experimentation in this regard, to try to figure out the maximum frequency that can be downshifted, and/or the minimum frequency that can be upshifted (and to what amount?) -- with respect to metasurfaces/layers of nanocrystals?

And of course -- what are the various problems encountered (probably more important than answering the above questions) when engaging in that line of research?

All I know is that the future looks very interesting, with a whole bunch of new (and possibly very weird!) future transducers based on this technology!

Also, with the right transducers available -- the world would take a step closer to full-on Optical Computing...

Does the generated light preserve the incoming direction of the source IR? If not, then you'll still need some sort of lens to focus the IR onto the film, and then (if your eye is close to the film) another lens to let you focus on the film. So, nothing like the concept image of glasses enhancing the scenery.

Anyone know if the performance is good enough to bring it into scope of arms control laws?

As I understand it if you make (very) high performance night vision you may not be able to sell it to civilians under current regulations.