Light scattering of particles illuminated by a divergent beam

Analysis on particle size distribution is very important to a wide variety of industrial processes. A new measurement system of laser diffraction analyzer, in which a divergent beam is used as the incident light, is presented in this paper. Analytical expressions are obtained to describe the spatial distribution of the scattered light in the detection plane under or without the paraxial approximation. The results show that the new measurement system behaves in a similar way to those of the laser diffraction analyzers with reverse Fourier optics (RFO) and is especially suitable for measurements on small particles.

► A new optical arrangement for measurements on small particles is presented.
► Influences of multi-reflections on the signals occurring in the reverse Fourier optics can be avoided in this system.
► Analytical expressions of scattered light on the detection plane are obtained based on the Mie theory.