Electrically Tunable Optical Metasurfaces for Dynamic Polarization Conversion.

Dynamic control over the polarization of light is highly desirable in many optical applications, including optical communications, laser science, three-dimensional displays, among others. Conventional methods for polarization control are often based on bulky optical elements. To achieve highly integrated optical devices, metasurfaces, which have been intensively studied in recent years, hold great promises to replace conventional optical elements for a variety of optical functions. In this work, we demonstrate electrically tunable optical metasurfaces for dynamic polarization conversion at visible frequencies. By exploring both the geometric and propagation phase tuning capabilities, rapid and reversible polarization rotation up to 90° is achieved for linearly polarized light. The dynamic functionality is imparted by liquid crystals, which serve as a thin surrounding medium with electrically tunable refractive indices for the metasurface antennas. Furthermore, we expand our concept to demonstrate electrically tunable metasurfaces for dynamic holography and holographic information generation with independently controlled multiple pixels.