CORE-RESONANCE CAPILLARY-FIBER WHISPERING-GALLERY-MODE LASER

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.