Spin characterization of high-stability optically levitated particles in dual-beam traps.

Optically levitated spinning particles demonstrate significant promise for inertial sensing, precision measurement, and quantum science. However, the levitation and rotation of micro-vaterite particles primarily rely on a single trapping laser beam, severely limiting both stability and rotational capability. Although dual-beam configurations can improve trapping stiffness, they have not yet achieved stable high-rate spinning of vaterite particles. In this work, two counter-propagating beams with opposite circular polarization have been used to levitate and drive 3.58-μm-diameter vaterite particles to high spin rates. Compared to single-beam traps, our approach achieves a two-order-of-magnitude improvement in translational oscillation frequency and spin rate under atmospheric conditions. It achieved 6-MHz rotation at a moderate pressure of 20 Pa without enhancing thermal motion at low pressures. Meanwhile, the orientation of the particle under varying pressure conditions was characterized, revealing a fivefold improvement in orientational stability. This work provides a stable platform for high-rate spinning of particles, with significant potential applications in sensing and physical research.