We report lasing characteristics of 40–60-μm-diameter Rhodamine 590/water solution droplets pumped by a 20-nsec-duration Q-switched laser. The Rhodamine/water solution provides a useful model system for studying the properties of oscillators based on whispering-gallery-wave spherical cavities. The low threshold for lasing, 104 W/cm2 for 10−4M solutions, is consistent with particle size and a cavity Q factor of 104. Portions of the droplet lase purely in transverse electric (TE) modes, while other portions contain both TE and lower-Q transverse magnetic modes. In the far field, the lasing droplet approximates a coherent point source emitting in all directions.
© 1986 Optical Society of America
Original Manuscript: May 19, 1986
Manuscript Accepted: July 9, 1986
Published: October 1, 1986
H.-B. Lin, A. L. Huston, B. L. Justus, and A. J. Campillo, "Some characteristics of a droplet whispering-gallery-mode laser," Opt. Lett. 11, 614-616 (1986)