We propose a novel physical mechanism based on periodic non-Hermitian potentials to efficiently control the complex spatial dynamics of broad-area lasers, particularly in vertical-cavity surface-emitting lasers (VCSELs), achieving a stable emission of maximum brightness. A radially dephased periodic refractive index and gain-loss modulations accumulate the generated light from the entire active layer and concentrate it around the structure axis to emit narrow, bright beams. The effect is due to asymmetric inward radial coupling between transverse wave vectors for particular phase differences of the refractive index and gain-loss modulations. Light is confined into a central beam with large intensity, opening the path to design compact, bright, and efficient broad-area light sources. We perform a comprehensive analysis to explore the maximum central intensity enhancement and concentration regimes. This Letter reveals that the optimum schemes are those holding unidirectional inward coupling, but not fulfilling a perfect local PT-symmetry.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): BAS/1/1626-01-01, OSR-2016-CRG5-2950
Acknowledgements: King Abdullah University of Science and Technology (KAUST) (BAS/1/1626-01-01, OSR-2016-CRG5-2950); Spanish Ministerio de Economía y Competitividad (MINECO) (FIS2015-65998-C2-1-P); European Union Horizon 2020 Framework Programme (H2020) EUROSTARS (E10524 HIP-Laser).