Self-waveguiding of light pulses in photorefractive BSO crystals: intensity and polarization dynamics

We numerically analyze the selfocusing process of laser pulses propagating inside a photorefractive BSO crystal, simulating the carrier dynamics inside the material. We demonstrate that the soliton regime cannot be reached because of the delay of the photorefractive response in comparison to the excitation. As a consequence only relatively long pulses can efficiently excite the photorefractive nonlinearity, which is able to partially confine the pulse. The confined part has the typical polarization dynamics of a soliton in an optically active media, while the initial part just diffracts following a polarization dynamics which evolves towards the linear regime..