title: Vortex Laser based on III-V semiconductor metasurface: direct generation of coherent Laguerre-Gauss modes carrying controlled orbital angular momentum.
abstract: The generation of a coherent state, supporting a large photon number, with controlled orbital-angular-momentum L = ħl (of charge l per photon) presents both fundamental and technological challenges: we demonstrate a surface-emitting laser, based on III-V semiconductor technology with an integrated metasurface, generating vortex-like coherent state in the Laguerre-Gauss basis. We use a first order phase perturbation to lift orbital degeneracy of wavefunctions, by introducing a weak anisotropy called here "orbital birefringence", based on a dielectric metasurface. The azimuthal symmetry breakdown and non-linear laser dynamics create "orbital gain dichroism" allowing selecting vortex handedness. This coherent photonic device was characterized and studied, experimentally and theoretically. It exhibits a low divergence (<1°) diffraction limited beam, emitting 49 mW output power in the near-IR at λ ≃ 1 μm, a charge l = ±1, … ±4 (>50 dB vortex purity), and single frequency operation in a stable low noise regime (0.1% rms). Such high performance laser opens the path to widespread new photonic applications.
authors.affiliation: IES, CNRS-UMR 5214, Université Montpellier, France.
authors.forename: Mohamed S
authors.initials: MS
authors.lastname: Seghilani
authors.affiliation: IES, CNRS-UMR 5214, Université Montpellier, France.
authors.forename: Mikhael
authors.initials: M
authors.lastname: Myara
authors.affiliation: IES, CNRS-UMR 5214, Université Montpellier, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Sellahi
authors.affiliation: Laboratoire de Photonique et Nanostructures, CNRS-UPR 20, Marcoussis, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Legratiet
authors.affiliation: Laboratoire de Photonique et Nanostructures, CNRS-UPR 20, Marcoussis, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sagnes
authors.affiliation: Laboratoire de Photonique et Nanostructures, CNRS-UPR 20, Marcoussis, France.
authors.forename: Grégoire
authors.initials: G
authors.lastname: Beaudoin
authors.affiliation: Laboratoire Photonique, Numérique et Nanosciences, CNRS-UMR5298, Institut d'Optique d'Aquitaine, Talence, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lalanne
authors.affiliation: IES, CNRS-UMR 5214, Université Montpellier, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Garnache