Pascal Del'Haye

Two beams of light, red and blue, enter a tiny ring made of silicon nitride. The ring is smaller than the thickness of a human hair. At the input, both beams are equally bright. But inside the ring, one of them suddenly starts to outshine the other, like two equally matched people in a debate where one unexpectedly gains the upper hand.

The nucleus of a thorium-229 atom is like a taut guitar string: it vibrates at a strictly defined frequency. To 'pluck the string', a precise strike is needed — a laser beam of a very specific color.