Chaohao Chen

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.

On the table lies a layered cake of hexagonal boron nitride flakes, a material similar to graphite but made of boron and nitrogen atoms. One flake is carefully transferred onto another, and at the spot where they overlap, after heating in oxygen, bright single light sources are born.