Light scattering by microdroplets of water and water suspensions

We investigated elastic light scattering on isolated evaporating droplets of radius between 1 and 20 μm. The droplets were either pure water or a water based suspension, they carried electric charge and were contained in an electrodynamic trap. The evolution of the trapped droplet was investigated by means of scatterometry. A numerical model of such evolution, incorporating the kinetic effects near the droplet surface was constructed. For water droplets with spherical inclusions the radius as well as effective refractive index was determined. An essential deviation, in the form of a resonance, from predictions by standard effective medium theories was encountered. Simple analysis of the phenomenon was conducted and a qualitative explanation is proposed. Similar analysis was applied to fullerene water suspension droplets in order to investigate the real part of refraction index.