Abstract

We report observations of lasing and fluorescence emission from liquid microdroplets of fluorescein 548 dye in ethanol, seeded with submicrometer sized fluorescent sol. An incident pump laser generates droplet fluo­rescein lasing or fluorescene, which in turn excites either fluorescene or lasing in the sol. All emissions are at wavelengths corresponding to morphology dependent reso­nances (MDR's) of the droplet. Studies of the dependence of these emissions on pump laser intensity and sol concentration suggest they are driven by enhanced radiative energy transfer that occurs when fluorescein lasing or fluorescence emission couples to MDR's of the droplet microcavity. Other noteworthy findings include the absence of sol emission for larger sol and the presence of sol emission, even without any observable fluorescein emission, for smaller sol.

© 1992 Optical Society of America