Simultaneous determination of particle size and refractive index by time-resolved Mie scattering

With this numerical study we have investigated the pulse-induced and time-resolved Mie scattering with the aim of determining the size and the refractive index of transparent spherical particles simultaneously. The temporal interval between the scattering light signals of two different orders of scattered light allows only particle sizing. But if it is possible to detect three different orders of scattered light, then we have two independent time intervals. This situation is given if the detector has a position about θ=90°. With these scattering angle signals of reflection and refraction of 1st and 3rd order appear with approximately the same intensity. Then the numerical quotient of the two temporal intervals between these scattering orders is a function of the refractive index only. We have calculated these specific quotients by models of geometric optics for 1.1≤m≤1.6 and 75°≤θ≤90° and have seen that there is a very high agreement with the results of time-resolved Mie calculations.