Directional output emission from ring microlasers with broken rotational symmetry

Injection semiconductor microlasers with a 15-$\mu$m-radius ring resonator and an asymmetrically positioned internal resonator aperture are studied. It is shown that the asymmetry results in the formation of two directional radiation lobes in the radiation pattern, misaligned by 50 degrees relative to the internal aperture's offset axis. The measured Q-factor of the resonators is comparable to that of disk resonators and is at a level of $\sim$10$^6$.