Hardware-in-the-loop simulation research on cooling effect of different modulated waveform signals with vacuum optical trap parameter feedback

Abstract

Vacuum optical trap is a technology that captures and manipulates particles in a near-vacuum environment by means of laser mechanical effects. It is an ideal platform for precision measurement with high quality factor. Due to its low environmental damping, vacuum optical traps require feedback cooling to reduce the equivalent temperature of particle centroid motion to prevent particle escape. Parametric feedback cooling is a mainstream solution to achieve stable trapping of particles in optical traps. Monte Carlo method and finite difference method were used to simulate the displacement fluctuation of the microsphere without feedback, and the FPGA circuit was used to output control signals with different waveforms to test the feedback cooling effect. Under the premise of reaching mK cooling level, square wave control signals have advantages in fast feedback cooling, and sine wave control signals have advantages in maintaining phase matching.