Positive-Negative Tunable Liquid Crystal Lens of Rectangular Aperture

We propose a design method for liquid crystal lens with positive-negative tunable focal length and rectangular aperture. The designed electrodes produce a parabolic profile of voltage difference over the lens aperture. Parabolic phase profile is then obtained by controlling the voltage difference within the linear response range of liquid crystal materials, and high-quality performance liquid crystal lens can be realized. The principle of the design is described and the lens is demonstrated experimentally.