High-power directional emission from microlasers with chaotic resonators

High-power and highly directional semiconductor microcylinder lasers based on an optical resonator with deformed cross section are reported. In the favorable directions of the far-field, a power increase of up to three orders of magnitudes over the conventional circularly symmetric lasers was obtained. A 'bow-tie'-shaped resonance is responsible for the improved performance of the lasers in the higher range of deformations, in contrast to 'whispering-gallery'-type modes of circular and weakly deformed lasers. This resonator design, although demonstrated here in midinfrared quantum-cascade lasers, should be applicable to any laser based on semiconductors or other high-refractive index materials.