Researchers can now watch a single atom die inside a glass bead just by looking for the bead to 'jump' in a laser beam.
arXiv · March 17, 2026 · 2603.14979
The Takeaway
Usually, detecting radiation requires complex Geiger counters or sensors. This new method uses a tiny bead of glass held by light to detect the physical recoil and charge change the exact millisecond a single radioactive atom inside it decays.
From the abstract
We measure event-by-event discrete changes in the net electric charge of an optically levitated silica microsphere arising from individual radioactive decays within the sphere, in coincidence with energy depositions in a nearby scintillation detector. The net charge of the levitated sphere is continuously monitored by measuring its driven response to an oscillating electric field, allowing individual charge-change events to be resolved on millisecond timescales with precision below an elementary