Although biometric face-recognition security tech is now becoming quite common on devices such as smartphones, it does still require a lot of processing power. In the not-too-distant future, however, the same purpose could be served by an integrated piece of analog glass.

The new technology is currently being developed at the University of Wisconsin-Madison, by researchers Zongfu Yu, Ang Chen and Efram Khoram.

In a proof-of-concept exercise, the team created a small piece of translucent glass with tiny air bubbles and other light-bending or -absorbing impurities strategically embedded within it. When that glass was placed near one of nine surfaces that each had a different numeral hand-written upon it, light was reflected off that numeral and into the glass.

Depending on the shape of the numeral in question, the bubbles/impurities guided the light through the glass along a different path, delivering it to one of nine spots on the other side of the glass. Each of those spots corresponded to a specific numeral – so if the handwritten numeral was a 2, for instance, the bubbles would guide the light to illuminate the #2 spot.

Not only was the setup able to identify each individual numeral in its initial form, but when the scientists hand-altered a 3 to turn it into an 8, the glass likewise then interpreted it as an 8.

It is hoped that the technology could ultimately be used to recognize the distinct light patterns of a given person's facial features, illuminating a light sensor within a smartphone or other device only when that person held the device up to their face. The glass would reportedly be easy and inexpensive to fabricate.

"We could potentially use the glass as a biometric lock, tuned to recognize only one person's face" says Yu. "Once built, it would last forever without needing power or internet, meaning it could keep something safe for you even after thousands of years."

A paper on the research has been published in the journal Photonics Research. The video below has more.

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