Observation of sudden temperature jumps in optically levitated microdroplets due to morphology-dependent input resonances.

During the slow evaporation of an optically levitated microdroplet of a glycerol-water mixture (3:1) (approximately 12.44 µm in radius) several morphology-dependent input resonances have been observed in its Raman spectrum. These resonances yield sudden temperature jumps of approximately 10 °C in the microdroplet as evidenced by sudden shifts in the output (Raman) resonance spectra. The latter effects could be explained by a simple energy balance calculation and the dependence of droplet refractive index and density on temperature.