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dc.contributor.authorAhmed, Waqas Waseem
dc.contributor.authorHerrero, Ramon
dc.contributor.authorBotey, Muriel
dc.contributor.authorWu, Ying
dc.contributor.authorStaliunas, Kestutis
dc.date.accessioned2019-12-03T13:37:08Z
dc.date.available2019-12-03T13:37:08Z
dc.date.issued2019-10-17
dc.identifier.citationAhmed, W. W., Herrero, R., Botey, M., Wu, Y., & Staliunas, K. (2019). Brightness Enhancement in Non-Hermitian VCSELs. 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC). doi:10.1109/cleoe-eqec.2019.8873173
dc.identifier.doi10.1109/CLEOE-EQEC.2019.8873173
dc.identifier.urihttp://hdl.handle.net/10754/660396
dc.description.abstractVertical Cavity Surface Emitting lasers (VCSELs) are compact and efficient light sources useful for a variety of applications. However, due to lack of a transverse mode control mechanism, such lasers suffer from poor spatial beam quality, intrinsic spatiotemporal instabilities and nonlinear destabilizing effects such as filamentation and spatial hole burning [1]. Therefore, there is a need for new strategies to manipulate the light wave dynamics to enhance the stability of VCSELs. Recently, non-Hermitian media have become a flexible platform for new functionalities such as asymmetric coupling, unidirectional invisibility, single mode lasing [2–3]. In this presentation, we propose a novel stabilization mechanism for VCSLEs to obtain bright and narrow beams. The mechanism relies on non-Hermitian configuration of the laser potential, achieved by simultaneous spatial modulation of the refractive index and gain-loss profiles. In particular, we consider axisymmetric non-Hermitian potentials expressed as: n(r)=nR cos(qr)-inI cos(qr-ϕ) where nR and nI are the amplitude of the refractive index and gain-loss modulations, and ϕ is the relative phase shift between them. Such potentials may confine the emitted light around the central part of VCSELs, through unidirectional-inward radial coupling among the transverse modes [4]. The interplay of the relative strength and relative phase of the index and gain-loss modulations manipulate the wave dynamics of such lasers to emit powerful and narrow beams of high brightness. We use the mean-field paraxial model to study the spatiotemporal dynamics of such VCSELs with non-Hermitian potentials. The output emission of conventional VCSEL and modified VCSEL with concentric non-Hermitian configuration is shown in Fig. 1(a,b), illustrating irregular and stable localized pattern, respectively. We assess the performance through the central intensity enhancement [see Fig. 1(c)] and field concertation [see Fig. 1(d)]. The spatial dynamics for a representative point is provided in Fig. 1(e). The stationary intensity profile and its corresponding cross-section show that intensity is strongly concentrated at r=0 due to the favoured radial coupling of inward propagating waves, as depicted in the transverse field flow on the inset [see Fig. 1(e)].
dc.publisherInstitute of Electrical and Electronics Engineers (IEEE)
dc.relation.urlhttps://ieeexplore.ieee.org/document/8873173/
dc.relation.urlhttps://ieeexplore.ieee.org/document/8873173/
dc.relation.urlhttps://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8873173
dc.rights(c) 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
dc.titleBrightness Enhancement in Non-Hermitian VCSELs
dc.typeConference Paper
dc.contributor.departmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
dc.contributor.departmentApplied Mathematics and Computational Science Program
dc.conference.date23-27 June 2019
dc.conference.name2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
dc.conference.locationMunich, Germany
dc.eprint.versionPost-print
dc.contributor.institutionDepartament de Física, Universität Politècnica de Catalunya (UPC), Colom 11, E-08222 Terrassa, Barcelona, Spain
dc.contributor.institutionDepartament de Física, Universität Politècnica de Catalunya (UPC), Colom 11, E-08222 Terrassa, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, E-08010, Barcelona, Spain
kaust.personAhmed, Waqas Waseem
kaust.personWu, Ying
refterms.dateFOA2019-12-05T06:46:41Z


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