Novel Liquid Crystal Grating with a Relief Structure by a Simple UV Irradiation Process

A novel method of fabricating a liquid crystal grating is proposed. The liquid crystal grating, which has a periodic groove structure, can be fabricated by a simple single-step process with UV irradiation through a grating photomask using a mixture of liquid crystal and prepolymer materials. Phase separation in the UV curing process leads to completely separated layers of liquid crystal and polymer sections with the surface-relief grating structure. The grating structure of the cured polymer layer is investigated by using a polarizing microscope and a scanning electron microscope (SEM). Voltage control property of the diffraction efficiency is also investigated and the applicability of this liquid crystal grating to an electrical switchable diffraction device is discussed.