Micrometer-sized droplets of Rhodamine 6G solution in water and ethanol are irradiated by high-intensity nanosecond pulses from a frequency-doubled Nd:YAG laser. Coupling of the spontaneous fluorescence emission with natural resonant modes of the spherical droplets results in stimulated emission, with each droplet behaving like a laser cavity. Spectral observations suggest that droplet lasing emission is supported by resonances of a single mode order. The emission exhibits faster rise times and is shorter lived than corresponding bulk-liquid fluorescence. Lasing in droplets is generally initiated almost simultaneously with elastic scattering, unlike stimulated Raman scattering, which is significantly delayed.
© 1989 Optical Society of America
Original Manuscript: August 1, 1988
Manuscript Accepted: November 30, 1988
Published: February 15, 1989
A. Biswas, R. G. Pinnick, H. Latifi, and R. L. Armstrong, "Time-resolved spectroscopy of laser emission from dye-doped droplets," Opt. Lett. 14, 214-216 (1989)