Switchable Lasing in Multimode Microcavities

We propose the new concept of a switchable multimode microlaser. As ageneric, realistic model of a multimode microresonator a system of two coupleddefects in a two-dimensional photonic crystal is considered. We demonstratetheoretically that lasing of the cavity into one selected resonator mode can becaused by injecting an appropriate optical pulse at the onset of laser action(injection seeding). Temporal mode-to-mode switching by re-seeding the cavityafter a short cool-down period is demonstrated by direct numerical solution. Aqualitative analytical explanation of the mode switching in terms of the laserbistability is presented.Comment: Accepted for publication in Physical Review Letters. Published, somewhat shortened versio