Fully dynamic multiple-beam optical tweezers.

We demonstrate a technique for obtaining fully dynamic multiple-beam optical tweezers using the generalized phase contrast (GPC) method and a phase-only spatial light modulator (SLM). The GPC method facilitates the direct transformation of an input phase pattern to an array of high-intensity beams, which can function as efficient multiple optical traps. This straightforward process enables an adjustable number of traps and realtime control of the position, size, shape and intensity of each individual tweezer-beam in arbitrary arrays by encoding the appropriate phase pattern on the SLM. Experimental results show trapping and dynamic manipulation of multiple micro-spheres in a liquid solution.