Non-Hermitian broad aperture semiconductor lasers based on PT-symmetry

Abstract

In this paper we propose a novel configuration to regularize the complex spatiotemporal dynamics of broad area lasers into bright light beam. It has recently been shown that arbitrary non-Hermitian optical potentials based on local Parity-Time (PT-) symmetry may tailor and control the flow of light, due to the asymmetric mode coupling. We now provide a comprehensive analysis on how this can be applied to stabilize the emission from broad aperture semiconductor lasers. The mechanism relies on a non-Hermitian configuration of the laser potential achieved by simultaneous spatial modulation of the refractive index and gain-loss profiles. This allows concentrating the light into a bright and narrow output beam. We provide a numerical analysis on Vertical Cavity Surface Emitting lasers and Broad Area Semiconductor Lasers. The results indicate a significant intensity enhancement and concentration of the emitted stabilized beam. The proposed mechanism may be technologically achievable, and it is expected to be applicable to regularize the radiation of other broad aperture and microlasers, which typically emit quite random and irregular light patterns. Besides, the reported concentration effect is universal, and could be extended to random and quasi-periodic background potentials.