3-DIMENSIONAL POTENTIAL ANALYSIS OF RADIATION PRESSURE EXERTED ON A SINGLE MICROPARTICLE

A system that makes it possible to precisely and instantaneously obser ve a potential energy of laser trapping as a function of three-dimensi onal position was developed for analyzing radiation pressure acting on a single microparticle in solution. Position sensing with a quadrant photodiode and total internal reflection microscopy are applied for me asuring thermal Brownian motion of the trapped particle with similar t o 10 nm resolution, and a trapping potential profile is estimated by a thermodynamical analysis based on the Boltzmann distribution. Charact eristic features of the present system are discussed. (C) 1997 America n Institute of Physics.