0000000000161261
AUTHOR
C. O. Weiss
Experimental approach to transverse wave-number selection in cavity nonlinear optics
Spontaneous transverse pattern formation is experimentally studied in a ${\text{BaTiO}}_{3}$ photorefractive oscillator under degenerate four-wave mixing conditions. A near self-imaging resonator of high Fresnel number and quasi-one-dimensional in the transverse plane is used. A fine control technique of the cavity detuning, $\ensuremath{\Omega}$, is described. It allows a precise study of the relation of $\ensuremath{\Omega}$ with the transverse wave number ${k}_{\ensuremath{\perp}}$ of the roll patterns selected by the system. The law ${k}_{\ensuremath{\perp}}^{2}=\ensuremath{-}\ensuremath{\Omega}∕a$ is verified, which evidences that wave-number selection is mainly dictated by the cavity …
Ising-Bloch transition in 2D degenerate wave mixing
We show experimentally and theoretically the existence of a 2D Ising-Bloch transition in the field generated by degenerate four wave mixing in a BaTiO3-resonator.
Ising and Bloch walls of phase domains in two-dimensional parametric wave mixing
Oscillators driven by a degenerate wave mixing process are bistable in the phase of the generated radiation. In systems with a large Fresnel number, domains of opposite phase form therefore spontaneously. A simple model predicts a real field in which phase domains are separated by Ising-type walls. In this paper we show experimentally (using complex field reconstruction from measurements) and theoretically (by an extended model) that the optical field can be real as well as complex valued and that complex field fronts are related to the front curvature.
Deviation from Lorenz-type dynamics of an NH3 ring laser
Abstract We show that the differences of the intensity spiral dynamics of an optically pumped NH 3 ring laser from that of the Lorenz model are caused by counterpropagating emission and by three-level coherence effects. In particular we find that under appropriate conditions the differences disappear and the laser emits purely according to the Lorenz model.