Microparticle sorting using optical obstacle arrays

Abstract

We present optical obstacle arrays as a novel scheme for laser-induced sorting of colloidal particles. The generalized phase contrast method is used to construct a two-dimensional intensity distribution composed of periodic dark sites in a bright background field. Such an optical landscape represents a series of optical obstacles that deflect the motion of high refractive index microparticles carried by a moving fluid. Preliminary results show the potential for optical obstacle arrays to sort microparticles according to size.