title: Pattern-dislocation-type dynamical instability in 1D optical feedback Kerr media with Gaussian transverse pumping.
abstract: We study experimentally and numerically the secondary instability corresponding to the destabilization of stationary transverse roll patterns appearing in a 1D liquid crystal layer subjected to optical feedback. This dynamical instability appears as roll dislocations in the spatiotemporal diagrams. We show that it originates from the Gaussian spatial transverse dependence of a control parameter and that its corresponding mechanism is the selection of a local unstable wave number. This instability is the optical counterpart of the ramp-induced Eckhaus instability observed in hydrodynamics.
authors.affiliation: Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523, Centre d'Etudes et de Recherches Lasers et Applications, Université des Sciences et Technologies de Lille, F-59655 Villeneuve d'Ascq Cedex, France.
authors.forename: E
authors.initials: E
authors.lastname: Louvergneaux