Passive Resonances and Active Lasing Modes in a Chaotic Microcavity

Passive resonances and active lasing modes in a spiral-shaped dielectric microcavity are investigated. We find that the high-Q resonances are whispering-gallery-like modes, and these resonance modes can be easily excited as lasing modes. We also find that the quasi-scarred resonance, which shows strong directional emission beams from the cavity boundary, can be excited with selectively applied external pumping. As a result, we find that the final quasi-stationary lasing pattern exhibits multimode oscillation of whispering-gallery-like mode and quasi-scarred mode