title: Analysis of broad emission direction in a spiral-shaped microcavity laser.
abstract: Broad emission direction with two lobes is analyzed in a spiral-shaped microcavity laser. By pumping the boundary of the InGaAsP semiconductor laser with dc current injection, whispering-gallery-type modes emitting through a notch are obtained. By classifying the lasing modes into mode groups based on the equidistant mode spacing, it is shown that each mode group has its own emission direction with a narrow divergence angle and that a superposition of emission direction of dominant mode groups reproduces a far-field pattern of total intensity with two lobes, which is contrary to theoretical results.
authors.affiliation: Department of Physics, Sogang University, Seoul 121-742, South Korea.
authors.forename: Myung-Woon
authors.initials: MW
authors.lastname: Kim
authors.forename: Kyu-Won
authors.initials: KW
authors.lastname: Park
authors.forename: Chang-Hwan
authors.initials: CH
authors.lastname: Yi
authors.forename: Chil-Min
authors.initials: CM
authors.lastname: Kim