This study investigates the beam profile and the liquidcrystal (LC) arrangement affected by an optical field on LC thin films at a temperatureclose to nematic–isotropic phasetransitiontemperature (TNI). A combined microscopic and conoscopic technique was used in experiments as a convenient way to analyze the opticalnonlinearity that is associated with the molecular configuration of nematicliquidcrystal (NLC). An optical field combined with thermal enhancement enhances molecular reorientation and causes additional molecular excitation along the axis of propagation of the beam. The reorientational nonlinearity yields an undulating structure with multi-foci; the length between each pair of foci increases with time, as described
