Non-Hermitian arrangement for stable semiconductor laser arrays

TL;DR

This paper introduces a non-Hermitian, PT-symmetric coupling mechanism to stabilize and enhance the emission of semiconductor laser arrays, improving temporal stability and output brightness.

Contribution

It presents a novel physical mechanism using non-Hermitian potentials for stabilizing laser array dynamics and demonstrates its effectiveness through detailed numerical models.

Findings

Achieved temporal stabilization of laser arrays.

Enhanced light emission and spatial redistribution.

Controlled field concentration on central lasers.

Abstract

We propose and explore a physical mechanism for the stabilization of the complex spatiotemporal dynamics in arrays (bars) of broad area laser diodes taking advantage of the symmetry breaking in non-Hermitian potentials. We show that such stabilization can be achieved by specific pump and index profiles leading to a PT-symmetric coupling between nearest neighboring lasers within the semiconductor bar. A numerical analysis is performed using a complete (2+1)-dimensional space-temporal model, including transverse and longitudinal spatial degrees of freedom and temporal evolution of the electric field and carriers. We show regimes of temporal stabilization and light emission spatial redistribution and enhancement. We also consider a simplified (1+1)-dimensional model for an array of lasers holding the proposed non-Hermitian coupling with a global axisymmetric geometry. We numerically demonstrate a two-fold benefit: the control over the temporal dynamics over the EELs bar and the field concentration on the central lasers leading to a brighter output beam, facilitating a direct coupling to an optical fiber.