Beam propagation in nematic liquid crystals

We investigate the behavior of beams propagating in nematic liquid crystals. A spatiotemporal model for the beam propagation and the director reorientation in a nematic liquid crystal is treated numerically in three spatial dimensions and time. We demonstrate the formation of stable solitons in a narrow threshold region of beam intensities for a set of fixed parameters and display soliton breathing. Below the threshold region the beams diffract, above the region spatiotemporal instabilities are observed, as the input intensity and the optical and static permittivity anisotropies of the liquid crystal molecules are increased. We demonstrate the filamentation of solitons above the threshold with increasing input intensity.