Laser diagnostics for droplet characterization: Application of morphology dependent resonances

A micron-sized liquid droplet acts as a very high-quality factor optical cavity. The cavity modes are referred to as morphology-dependent resonances (MDRs), which are sensitive to the droplet size, shape, and inclusions. The MDRs greatly lower the input intensity needed to generate detectable amounts of linear and nonlinear optical radiation and exhibit sharp peaks in the spectra of elastic scattering, fluorescence, lasing, and stimulated Raman scattering. Novel spectroscopic-based techniques are now available for droplet diagnostics of its physical, chemical, and thermal properties. In particular, we will review how MDR related spectroscopy can be used to deduce:he droplet size, shape, evaporation rate, surface tension, viscosity, near-surface temperature, species, and species concentration in multicomponent droplets. Published by Elsevier Science Ltd.