Stimulated Raman scattering from individual water and ethanol droplets at morphology-dependent resonances

Abstract

Stimulated Raman scattering (SRS) from an individual liquid droplet (~30-microm radius) has been observed for H(2)O, D(2)O, and ethanol. The occurrence of a series of spectrally narrow peaks that are regularly spaced in wavelength is consistent with morphology-dependent resonances of the droplet, which acts as an optical resonator. The input intensity required to achieve the SRS threshold for the droplet is considerably less than that for the liquid in an optical cell.