Instability threshold and stability of non-hexagonal patterns in a photorefractive feedback system

This study investigates spontaneous pattern formation in a single mirror feedback system with a photorefractive nonlinearity. This paper also presents a detailed experimental investigation of the instability threshold for a wide range of system parameters. Fourier filtering techniques are employed experimentally in order to determine the unstable transverse wave numbers for a given set of parameters. The results are compared with the predictions obtained by the linear stability analysis and numerical treatment of the model equations.