Optoacoustic Detection of Microparticles in Liquids at Laser Fluences Below the Optical Breakdown Threshold

Abstract

An optoacoustic device consisting of a XeCl excimer laser and a measurement cell with an attached piezotransducer was used for detecting microparticles suspended in liquid probes. The potential of optoacoustic diagnostics of microinhomogeneous liquids was enhanced by applying informative parameters of optoacoustic response. Probes of distilled water and Dow Chemical latex suspension were used in experiments. It was shown that cavitation mechanism of optoacoustic conversion taking place at laser fluences below the optical breakdown threshold was well-suited for individual microparticle detection. The approach proposed is different from the well-known breakdown counting optoacoustic technique.