SPATIAL STABILITY OF PARTICLES TRAPPED BY TIME-DIVISION OPTICAL TWEEZERS

We developed an on-demand multiple-spot holographic optical tweezers (HOT) system based on quasi-simultaneous generation of two intensity-spot patterns by alternately sending the two corresponding hologram patterns to a spatial light modulator. This switching operation reduces the spatial stability of a Brownian particle trapped inside the generated intensity spot. In this study, numerical analysis of the conditions for stable particle trapping in the time-division HOT is conducted using the Smoluchowski equation under the Rayleigh scattering approximation. The relationship between the particle size, the switching rate, and the focused laser beam power is obtained. Experiments confirm the validity of the numerical analysis.