Beam divergence of surface-emitting semiconductor laser with resonator based on two-dimensional photonic crystal

Theoretical calculations of the resonator modes optical characteristics of a semiconductor surface-emitting laser with a resonator based on a two-dimensional photonic crystal with a square lattice were carried out in the paper. Photonic crystal provides distributed feedback in plane of heterostructure layers and determines diffraction of radiation to the surface of the laser structure. Output beam emitted in the direction normal to the surface of such devices allows decreasing the beam divergence and increasing the output optical power. However, an increase in radiation aperture also affects the mode composition of the laser emission. The dependences of resonator modes optical losses and beam divergence on cavity size were obtained. A suggestion of the optimal cavity length to achieve single-mode operation with small output laser beam divergence angle was made.