Mehran Kianinia

A glowing spot on a crystal is like a firefly that you can wake not only with a flashlight but also with the warmth of your palm. Such spots, single-photon sources, can emit light one particle at a time, which is essential for quantum communication and computing.

A tiny defect in a boron nitride crystal behaves like a microscopic indicator bulb. Shine light on it, and it glows, with the shade shifting with temperature: the warmer it gets, the redder the glow.