Two-dimensional diffraction grating based on polymer-dispersed liquid crystals

An electrically tunable two-dimensional (2D) diffraction grating is demonstrated using nanosized liquid crystal droplets dispersed in a polymer matrix. A pixel-wall photomask is positioned in contact with a polymer-dispersed liquid crystal (PDLC) film during curing to control the rate of polymerization. The cured inhomogeneous composite film exhibits high transmittance and phase retardation between the high- and low-intensity regions. Such a film can be utilized as a diffraction grating that is polarization dependent and electrically tunable. It has a potential in optical beam steering.