Laser sheet drop sizing using Raman and Mie scattering

The knowledge of droplet size distribution is very important in different medical, pharmaceutical and technical applications. Researchers in all these fields are interested in a temporally and spatially resolving two-dimensional measurement technique. A new approach for the two-dimensional determination of the droplet size is the use of two different imaging measurement techniques whose signal intensities have different dependences on the particle size. The combination of laser Raman scattering with Mie scattering is presented here. Whereas Raman scattering intensities are dependent on the measurement volume and Mie scattering on the surface, the ratio of the signal intensities of the inelastically and the elastically scattered light is therefore proportional to the droplet size. The challenge by the application of this combination of measurement techniques, the advantages and the evaluation strategy will be described exemplary shown by measurements of a single droplet chain.