Lightbeans

Beyond cutting and reading, the most astonishing applications of light beams emerge when they interact with matter in non-linear ways. When an ultra-short pulse of light—a femtosecond laser beam lasting one quadrillionth of a second—is focused into a transparent material like glass, something magical happens. The intensity is so high that it causes multi-photon absorption: the glass suddenly becomes opaque at the beam’s focal point, absorbing the energy and creating a tiny plasma bubble. By moving the beam, one can etch three-dimensional structures inside the glass, creating data storage that can last for millennia.