Measurement of particle size and refractive index using crossed-beam laser anemometry

Abstract

The light scattered by spherical particles crossing the test space of a laser fringe anemometer is monitored simultaneously at two angles. From the visibilities of the signals the particle size distribution and one component of the refractive index may be determined. For non-absorbing particles this is the complete refractive index. Measurements were made on a water spray, glass ballotini and titanium and aluminium oxide particles in flames. Spherical metal oxide particles were produced by the combustion of metal powder in an oxygen-rich methane flame. Extension to the measurement of the full complex refractive index is discussed.