A Nanostructure ‘Metalens’ is Coming to Revolutionize Photography and Surveillance

A new, hi-tech lens called a ‘metalens’ has reportedly come a step closer to being manufactured, according to research published in the journal Nature Nanotechnology.

A flat surface that uses extremely tiny nano-structures to focus light composes the metalens, and science websites are reporting that it could “change optics forever,” by replacing the common large, curved lenses cameras use now.

That means that this technology could enable cameras to become unbelievably tiny, possibly so tiny they can’t be easily seen.

Until now, these ultra-compact lenses have lacked the ability to focus a broad, true spectrum of light. However, researchers just developed a single metalens with the capability of focusing the entire spectrum of visible light. In the past, multiple lenses were required for making white light into one point at a high resolution.

Apparently the difficulty in creating a metalens like this lies in chromatic aberrations, errors in focusing that result from different wavelengths of light moving through materials at varying speeds. Traditional lenses overcome this with curved surfaces. Violet light moves through material the slowest, and red light moves the fastest.

Tiny metalenses can’t be curved like traditional lenses: so the SEAS research team used ultra tiny arrays of titanium dioxide, fins that are nano-sized to resolve the chromatic aberrations.

By probably tediously experimenting with paired units of the tiny nanofins, they managed to control the speed of different color lights passing through the lens, focusing each color in a single spot.

According to Science Alert:

“It’s almost like creating a miniature maze to guide different colours through the lens, and the team says the new technology can dramatically reduce thickness and design complexity compared to a standard multi-layered lens approach.

That goal is still some way off though: the next stage is to scale up the metalens to a 1 cm (0.39 inch) size, at which point the possibilities for VR, AR, standard cameras, microscopes and all kinds of optical technology really start to open up.”

“Metalenses have advantages over traditional lenses,” Federico Capasso, the lead researcher said. “Metalenses are thin, easy to fabricate and cost effective. This breakthrough extends those advantages across the whole visible range of light. This is the next big step.”

The article said “scale up” the lens to about 1/3rd of an inch for commercial use: so these lenses must be somewhere between the size of 1/4th of an inch in diameter, and the size of a grain of sand. That’s both incredible and terrifying.

Let’s play a game called “predict what the future will be like.” It’s a game we’re going to be playing for a long time.

The first thing that comes to my mind is: if cameras can get incredibly tiny due to technology that utilizes nano-structures to focus light, could cameras be placed where we might never dream they would appear? Could a smart dust surveillance type scenario arise from this, in which tiny cameras that look like dust are sprinkled into people’s homes to spy on them?

On the other hand, imagine seeing a shot filmed by say, a drone, from 4 different angles at once. What if you stuck these tiny-lens cameras onto a drone at 12 different spots and got 12 different video feeds?

Image: Jared Sisler/Harvard SEAS