High-Power Directional Emission from Microlasers with Chaotic Resonators
  High-power and highly directional semiconductor cylinder-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 magnitude 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. 
Claire Gmachl, Federico Capasso, E.E. Narimanov, Jens U.Noeckel,   A.Douglas Stone, Jerome Faist, Deborah L. Sivco and Alfre...