title: Vortex chain in a resonantly pumped polariton superfluid.
abstract: Exciton-polaritons are light-matter mixed states interacting via their exciton fraction. They can be excited, manipulated, and detected using all the versatile techniques of modern optics. An exciton-polariton gas is therefore a unique platform to study out-of-equilibrium interacting quantum fluids. In this work, we report the formation of a ring-shaped array of same sign vortices after injection of angular momentum in a polariton superfluid. The angular momentum is injected by a ℓ = 8 Laguerre-Gauss beam. In the linear regime, a spiral interference pattern containing phase defects is visible. In the nonlinear (superfluid) regime, the interference disappears and eight vortices appear, minimizing the energy while conserving the quantized angular momentum. The radial position of the vortices evolves in the region between the two pumps as a function of the density. Hydrodynamic instabilities resulting in the spontaneous nucleation of vortex-antivortex pairs when the system size is sufficiently large confirm that the vortices are not constrained by interference when nonlinearities dominate the system.
authors.affiliation: Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005 Paris, France.
authors.forename: T
authors.initials: T
authors.lastname: Boulier
authors.affiliation: Institut Pascal, PHOTON-N2, Université Clermont Auvergne, Blaise Pascal University, CNRS, 24 Avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: H
authors.initials: H
authors.lastname: Terças
authors.affiliation: Institut Pascal, PHOTON-N2, Université Clermont Auvergne, Blaise Pascal University, CNRS, 24 Avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: D D
authors.initials: DD
authors.lastname: Solnyshkov
authors.affiliation: Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005 Paris, France.
authors.forename: Q
authors.initials: Q
authors.lastname: Glorieux
authors.affiliation: Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005 Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Giacobino
authors.affiliation: Institut Pascal, PHOTON-N2, Université Clermont Auvergne, Blaise Pascal University, CNRS, 24 Avenue des Landais, 63177 Aubière Cedex, France.
authors.forename: G
authors.initials: G
authors.lastname: Malpuech
authors.affiliation: Laboratoire Kastler Brossel, UPMC-Sorbonne Universités, CNRS, ENS-PSL Research University, Collège de France, 4, place Jussieu Case 74, F-75005 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Bramati