SELECTION OF UNSTABLE PATTERNS AND CONTROL OF OPTICAL TURBULENCE BY FOURIER PLANE FILTERING

We report on selection and stabilization of transverse optical pattern s in a feedback mirror experiment. Amplitude filtering in the Fourier plane is used to select otherwise unstable spatial patterns. Optical t urbulence observed for nonlinearities far above the pattern formation threshold is stabilized by low-pass filtering of the optical power spe ctrum. Experimental observations obtained with a photorefractive nonli nearity are consistent with calculations based on a generic, cubic non linearity.