Overview
- Researchers at the Institute of Science and Technology Austria report in Physical Review Letters a method that levitates, charges, and measures single micron-scale silica aerosols in air using focused lasers.
- Measurements show the trapping light charges particles via a two-photon process that ejects electrons, increasing the particle’s positive charge step by step.
- During weeks-long observations, the team recorded abrupt spontaneous “microdischarges,” with charge drops on the order of tens of electrons.
- The electrode-free setup allows precise control of charging rates and uses weaker fields than many past lab studies, enabling continuous tracking of a single particle’s charge evolution.
- Independent experts call the precision impressive and see promise for probing droplet and ice charging, while cautioning that links to natural lightning remain unproven given the use of model silica particles and laser intensities stronger than sunlight.