Nuclear Clock - GoKawiil

Researchers detail fluorescence correction method for thorium-229 nuclear clock

Scientists working on a nuclear clock based on the thorium-229 isotope described how they processed fluorescence signal data to measure the transition's frequency accurately. Their method corrects for leftover excited-state population from prior measurements and for fluctuations in the vacuum-ultraviolet excitation power used to probe the nuclear transition.

nature.com · 2026-10-07

PTB team details 229.8 nm laser setup for thorium-229 nuclear clock feedback loop

Researchers describe a laser interrogation system built around a commercial frequency-quadrupled diode laser that reaches roughly 500 mW at 296.8 nm, used to probe a thorium-229-doped crystal sample. The setup combines offset-frequency phase locking and Pound-Drever-Hall stabilization to a reference cavity, with a photomultiplier tube detecting fluorescence signals inside a vacuum chamber, and the clock laser's frequency also compared against an optical frequency comb.

nature.com · 2026-10-07