Enhanced coupling to vertical radiation using a two-dimensional photonic crystal in a semiconductor light-emitting diode

Abstract
Enhanced coupling to vertical radiation is obtained from a light-emitting diode using a two-dimensional photonic crystal that lies entirely inside the upper cladding layer of an asymmetric quantum well structure. A sixfold enhancement in light extraction in the vertical direction is obtained without the photonic crystal penetrating the active material. The photonic crystal is also used to couple pump light at normal incidence into the structure, providing strong optical excitation.