A Never Before Seen Optical Trick Creates Ultra-Secure Cash

Via Fast Company (Technology) -

If all goes as planned, the world's supply of cash will soon be secured with a nano-scale optical defense that is as secure as it is visually impressive. Using arrays of holes no bigger than a virus, scientists at Toronto-based Nanotech Security have created an atoms-thick display that can be read by humans or machines and that shines with the brightness of a typical LED despite using nothing but reflected light.

The technology was inspired by the Blue Morpho butterfly, whose brilliant blue coloration comes not from pigment but the way that tiny holes in its scales reflect light. But the tech, called Nano-Optic Technology for Enhanced Security (NOtES), is different from the Morpho butterfly's wings, and pretty much all other bio-inspired reflective optical technologies, in that it is both extraordinarily thin and functions even in dim light.

NOtES exploits an obscure area of physics to accomplish its bright and sharp display, known as plasmonics. Light waves interact with the array of nano-scale holes on a NOtES display--which are typically 100-200 nanometers in diameter--in a way that creates what are called "surface plasmons." In the words of the company, this means light "[collects] on the films surface and creates higher than expected optical outputs by creating an electromagnetic field, called surface plasmonic resonance."