We describe the observation of laser emission at wavelengths corresponding to whispering-gallery modes from a highly refractive dye-doped solvent flowing in a normally illuminated silica capillary fiber. The cylindrical whispering-gallery-mode laser described here differs from the well-known spherical droplet laser in that it has an internal refractive index discontinuity. Boundary-value computations are presented that reveal that the feedback responsible for the observed lasing modes is associated with total internal reflection at the liquid–silica interface. No laser peaks are observed when the refractive index of the solvent is less than that of the silica.
© 1992 Optical Society of AmericaFull Article | PDF Article