Evanescent-wave pumped cylindrical microcavity laser with intense output radiation

A microcavity laser pumped by a pulsed evanescent optical wave is demonstrated. The laser radiates intense, linearly polarized light isotropically in a plane perpendicular to the axis of the cylindrical microcavity. The lasing was achieved by surrounding a small section of a glass capillary with a solution of rhodamine 6G and by coupling the pump light into the capillary wall. The laser modes are the whispering gallery modes which orbit in the capillary by total internal reflection. The laser gain is provided by the dye molecules around the capillary, where the evanescent waves of the modes spatially overlap with the evanescent part of the pump field. The lasing threshold pump energy was ∼100 nJ/pulse at a pump pulse duration of 6 ns.