Optical effects in liquid crystal cell with photosensitive chalcogenide glass substrate

Abstract

We report on the observation of dynamic light-induced annular patterns formation in a planar liquid crystal (LC) cell with chalcogenide microfilm As2S3 as orientating layer. The annular patterns appear under the irradiation of the cell by the laser beam (λ = 473 nm) with Gaussian distribution of intensity. The experimental results are explained in terms of the liquid crystal director reorientation in the LC cell after absorption of light by chalcogenide film. The director reorientation results in the LC refractive index change and formation of annular patterns in LC cell. To theoretically model the system under study we first minimized the total free energy functional subject to Gaussian-type modulation of the pretilt angle at chalcogenide covered substrate. Having found the director spatial profile we studied the light beam propagation through the cell with a spatially modulated pretilt angle. We determined the number of the aberration rings depending on the parameters of the laser beam and LC cell. We believe that light-induced change in the LC director anchoring at chalcogenide film can be applied to the development of various optical and electro-optical elements, such as dynamic micro-lenses, light controlled switchers and triggers, etc.