INPUT-OUTPUT RESONANCE CORRELATION IN LASER-INDUCED EMISSION FROM MICRODROPLETS

An experimental investigation of the effect of access to different resonant modes by pump laser radiation (input modes) on fluorescent emission spectra was performed on ethanol microdroplets. The droplets, containing approximate to 2 x 10(-7) M concentration of Rhodamine 6G dye as a fluorophor, were generated as a monodisperse stream with continuously variable sizes from approximate to 6.5 to 6.6 mu m in radius. This range of droplet size permitted Ar+ laser pump radiation (514.5 nm) to become resonant with the droplet for both TE and TM modes of orders 1-4. Emission spectra from 530 to 585 nm were obtained for each of the resolved input resonances. The results clearly show higher relative intensities in emission modes that have the same mode order as the pump radiation resonance. Convolution integrals of radial profiles of the input and output modes are consistent with the general pattern of observed spectral intensities.