Diffractive optical elements based on patterned photoalignment analogous to multi‐domain LCD alignment patterning, dammann grating (DG) and random grating (RG), are demonstrated in this paper. Diffractive optical devices can act as transparent displays or smart windows. Key to the fabrication of our gratings, which are photo‐aligned with azo‐type material, is the ability of the material to be rewritable, i.e. it usually realigns upon rewriting. Through controlling the electrical field applied to the grating, switching between diffractive and non‐diffractive states is possible. Our new approach to achieve electrically switchable gratings requires lower voltage driving voltages than either dynamic light scattering displays or PDLC based devices. Since our gratings operate with pure nematic liquid crystals without polymers, their response time are faster upon switching between transparent and opaque state.