Optical tweezers with light aligned along the particle's trajectory enable playing tennis with light rackets.

Droby, Ali; Attrash, Mohammad; Barhum, Hani; Shani, Nitzan; Roichman, Yael; Carmon, Tal · Sci Adv · 2025

basic_science · Level V

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Abstract

Optical tweezers can rapidly manipulate dielectric objects for applications ranging from microcentrifuges to controlling droplets and particles in a "lab-in-air" configuration. Here, we uniquely combine light propagation that is predominantly parallel to the particle's orbital track-rather than primarily perpendicular as in conventional vortices-with operation in air. We measure a 7-micrometer sphere circulating at 20,400 rounds per minute [340 hertz (Hz)] along 120-micrometer circumference tracks, achieving accelerations up to 10 times that of gravity (98 square meters per second). Our trap's optical orbital angular momentum of ℓ = 242ℏ per photon, combined with the gaseous environment, enables high circulation frequencies and underdamped operation at a high mechanical quality factor, <i><i>Q</i></i>. Together, our <i>Q</i>-<i>f</i> product of 5300 Hz facilitates low dissipation in combination with rapid particle manipulation. This advancement could substantially expand the impact of dynamic optical traps, particularly in fundamental measurements.