Optical evaluation of a double-layered ultrasound liquid crystal lens

A method to improve the performance of an ultrasound liquid crystal lens is proposed. A double-layer-based lens model tailored based on the liquid crystal's physical properties, e.g., its dielectric anisotropy and elastic constants, is presented as an alternative method to improve the lens's optical performance while forming weak anchoring surfaces for nematic liquid crystals, thus promoting easier reorientation of the liquid crystal molecules. The lens configuration was simulated by finite-element analysis using Ansys software. The lens's physical and optical characteristics were evaluated via comparison using two different liquid crystal materials: 5CB and RDP-85475. The birefringence distribution within the liquid crystal layer was investigated under ultrasound excitation, and the molecular angles of inclination were estimated. A higher birefringence distribution, greater molecular inclination, and a longer focal length were obtained for the double-layered liquid crystal lens using the 5CB material.