Interactive light-driven and parallel manipulation of inhomogeneous particles.

A light-driven micromanipulation system with real-time userfeedback control is used to simultaneously trap colloidal suspensions enabling a unique interactive sorting capability and arbitrary patterning of microscopic particles. The technique is based on a straightforward phase-tointensity conversion generating multiple beam patterns for manipulation of particles in the observation plane of a microscope. Encoding of phase patterns in a spatial light modulator, which is directly controlled by a computer, allows for dynamic reconfiguration of the trapping patterns, where independent control of the position, size, shape and intensity of each beam is possible. Efficient sorting of microsphere mixtures of distinct sizes and colors using multiple optical traps is demonstrated.