Size measurement of nanoparticles using the emission intensity distribution of laser-induced plasma

Abstract

A two-dimensional optical imaging method is presented for monitoring the laser-induced breakdown events of aqueous nanoparticles. The method is based on measuring the light intensity distribution of plasma from spatially resolved breakdown events. The number of laser breakdown events as a function of the emission intensity follows the Gaussian distribution and its full-width at a half-maximum appears in direct correlation with the particle size. Hence the particle size can be determined by measuring the plasma emission intensity distribution. Calibration of the method is carried out with reference polystyrene particles dispersed in water. Application is demonstrated for measuring bentonite colloidal particles of different sizes in groundwater.