Gradient pretilt angle alignment materials with different photosensitivity for tunable polarization-independent self-aligned liquid crystal lens

Abstract

Alignment of benzaldehyde materials with different photosensitivity thresholds, capable of changing the pretilt angles of nematic liquid crystal (LC) from 90 to 0 in a controlled manner under UV-B exposure, has been developed. Inhomogeneous exposure of uniform rubbed alignment layers allows the formation of a refractive index gradient inside the LC cell. The concept of tunable polarizationindependent self-aligned LC lens based on gradient pretilt angle alignment materials with different photosensitivity is demonstrated. Self-alignment of two polarization-dependent sub-lens is achieved due to a single exposure act of two alignment layers, which are located on the same piece of glass on both sides, forming one common optical axis for a polarization-independent LC lens. The sublens cells have uniform cell gap and are independently controlled using lowvoltage driving. Devices based on gradient benzaldehyde alignment materials can be used in many modern optical and photonic devices.