title: Spiral patterns, spiral breakup, and zigzag spirals in an optical device.
abstract: Above the first lasing threshold the degenerate optical parametric oscillator with saturable absorber displays successive Hopf and Turing instabilities. Various spiral patterns and defect turbulent patterns are numerically observed on the light intensity profiles. Close to the Hopf threshold, a normal form is derived which leads to a complex Ginzburg-Landau equation where a bi-Laplacian instead of a Laplacian drives the formation of spirals. At resonance the predictions of the normal form are compared with the numerical observations of the full equations. Above the Hopf threshold, the spirals destabilize, breaking into slowly evolving patterns with small spirals and filaments. Further above the threshold, when both the Turing and Hopf bifurcations interplay, a new spiral pattern emerges, with large notched arms.
authors.affiliation: Laboratoire de Photophysique du CNRS, Bâtiment 210, Université de Paris-Sud, 91405-Orsay, Cedex, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Le Berre
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ressayre
authors.forename: Andrée
authors.initials: A
authors.lastname: Tallet
authors.forename: Mustapha
authors.initials: M
authors.lastname: Tlidi