Trapping and Sorting Micro-Nano Particles in a Dynamic Optical Sieve

We propose a novel strategy for optical trapping and sorting of micro-nano particles that does not involve the flow of the immersion medium. The method employs the size- and velocity-dependent response of suspended polystyrene particles to the optical sieve of a dynamic fringelike pattern generated by a spatial light modulator. We not only experimentally demonstrate the trapping and transport of polystyrene particles with 2 μm diameter, but also study the sorting of a polydisperse suspension of polystyrene beads with diameters of 0.8 and 2 μm. The results provide new insights into particle manipulation and separation, and reveal that there is still scope for sorting smaller particles based on dynamic optical sieve.