Application of optical trapping to beam manipulation in optofluidics

We introduce a novel method of attaining all-optical beam control in an optofluidic device by displacing an optically trapped microsphere though a light beam. The micro-sphere causes the beam to be refracted by various degrees as a function of the sphere position, providing tunable attenuation and beam-steering in the device. The device itself consists of the manipulated light beam extending between two buried waveguides which are on either side of a microfluidic channel. This channel contains the micro-spheres which are suspended in water. We simulate this geometry using the Finite Difference Time Domain method and find good agreement between simulation and experiment. (c) 2005 Optical Society of America.