The behavior of tiny charged particles in our atmosphere remains one of science’s intriguing puzzles, shaping phenomena such as cloud formation and lightning strikes. To study these phenomena in a laboratory, researchers can suspend individual particles in laser traps created by optical tweezers. In a recent advance, an international collaboration (led by an Austrian experiment with theoretical insights from IFA) has developed a technique to precisely control the charge of a particle in a laser trap. This capability opens new possibilities for atmospheric studies. The team achieved this by exploiting a two-photon excitation process, which enabled fine-tuned charging while the particle remains in an optical tweezer.

The paper can be found https://journals.aps.org/prl/abstract/10.1103/5xd9-4tjj, see also https://physics.aps.org/articles/v18/s152 for a brief summary.