Spontaneous optical pattern formation in a nematic liquid crystal with feedback mirror

Abstract Spontaneous two dimensional transverse optical pattern formation has been observed in a simple feedback mirror experiment using a hybridly aligned nematic liquid crystal 5CB as a nonlinear optical medium. Grating wave-numbers of the patterns and threshold intensities are investigated as a function of the distance between the nonlinear film and the mirror. Comparison with a theoretical model of the reorientational optical nonlinearity and the present arrangement is presented.