Optical beam deflection signal from a single microparticle

Abstract
The optical beam deflection (OBD) method was applied to the measurement of a single microparticle, and the signal from one resin microparticle of 200–600 μm in diameter could be detected. Based on the frequency characteristics and size dependence of the OBD signal, this method was found to be more sensitive for a smaller particle, and more effective than the photoacoustic method. Theoretical considerations showed that these characteristics were attributable to the enhancement of the temperature field gradient due to the curvature of the microparticle.