Wide-angle emission and single-mode deformed circular microlasers with a flat side.

We demonstrate wide-angle emission and single mode operation in deformed circular microlasers with a flat side. The mode characteristics of a metallic confined deformed circular resonator with a flat side are investigated by finite-difference time-domain simulation. The numerical results indicate that this structure is suitable to realize wide-angle emission. Furthermore, metallic confined deformed circular microlasers with a flat side are fabricated using common photolithography and inductively coupled-plasma etching techniques. A continuous-wave single-mode operation with a side mode suppression ratio of 25 dB is achieved at an injection current of 4 mA for an 8 μm radius microlaser with a flat side. Additionally, wide angle emission over 120° is observed from the far-field pattern.