Nonlinear transverse effects in photorefractive liquid crystal light-valves

Photorefractive liquid crystal light-valves (LCLV) are built associating a liquid crystal layer with a thin Bi₁₂SiO₂₀ (BSO) photorefractive crystal [1]. The photoconductive and electro optic properties of the device are separately optimized. While the excellent photosensitivity arises from the photoconductivity of the BSO, the large electro-optic effect is due to the large birefringence of the liquid crystals. Photorefractive LCLVs have been demonstrated as attractive elements for nonlinear optical applications, such as two-wave mixing optical amplification and self-pumped phase conjugation [2]. Recently, we have introduced a new optical oscillator based on a photorefractive LCLV as a gain medium [3]. The large transverse size and high gain of the LCLV allows a large number of longitudinal and transverse modes to be simultaneously amplified in the cavity, thus giving rise to dynamical regimes remained inaccessible up to date. We report different dynamical regimes, in particular high amplitude spatiotemporal pulses that are confined along the three space directions.