Electrically tunable optical metasurfaces

Optical metasurfaces have emerged as a groundbreaking technology in photonics, offering unparalleled control over light-matter interactions at the subwavelength scale with ultrathin surface nanostructures and thereby giving birth to flat optics.While most reported optical metasurfaces are static, featuring well-defined optical responses determined by their compositions and configurations set during fabrication, dynamic optical metasurfaces with reconfigurable functionalities by applying thermal, electrical, or optical stimuli have become increasingly more in demand and moved to the forefront of research and development.Among various types of dynamically controlled metasurfaces, electrically tunable optical metasurfaces have shown great promise due to their fast response time, low power consumption, and compatibility with existing electronic control systems, offering unique possibilities for dynamic tunability of light-matter interactions via electrical modulation.Here we provide a comprehensive overview of the state-of-the-art design methodologies and technologies explored in this rapidly evolving field.Our work delves into the fundamental principles of electrical modulation, various materials and mechanisms enabling tunability, and representative applications for active light-field manipulation, including optical amplitude and phase modulators, tunable polarization optics and wavelength filters, and dynamic waveshaping optics, including holograms and displays.The review terminates with our perspectives on the future development of electrically triggered optical metasurfaces.