Lasing characteristics of a Limaçon-shaped microcavity laser

We investigate lasing characteristics of a Limaçon-shaped InGaAsP semiconductor microcavity laser. When the cavity is pumped with dc current, the laser generates directional emissions. Near the threshold a series of modes with equidistantly spaced resonant frequencies emit. From the mode spacing we confirm the emission of whispering gallery-type resonance modes. As the injection current increases, a single resonance mode becomes dominant with directional emission. The quality factor of the single mode is obtained near the threshold, which is larger than 22 000.