MEMS‐Tunable Bilayer Plasmonic Metasurfaces for Dynamic Vortex Wave Plates

Abstract Dynamic metasurfaces (MSs) have emerged as a transformative technology in miniaturized tunable optics, enabling reconfigurable optical responses and opening new avenues for compact, adaptive, and multifunctional optical design. Here, a microelectromechanical system (MEMS)‐tunable bilayer MS (MEMS‐BMS) is demonstrated for dynamic vortex wave plates (VWPs), achieved by integrating a thin‐film piezoelectric MEMS mirror with bilayer plasmonic nanostructures composed of differently sized anisotropic nanobricks oriented in various directions. By electrically actuating the MEMS mirror to precisely tune the MEMS‐BMS separation, independent 2D phase control at two distinct separation distances is enabled, allowing dynamic switching of the reflected beam between different vortex modes under circularly polarized light excitation. The switching between vortex beams with topological charges of l = 2 and l = −1 is achieved with high polarization conversion efficiency (>80%) and a fast response time (9 microseconds), while preserving the output circular polarization state. The developed MEMS‐BMS VWP with its high efficiency, fast response, and polarization preservation holds strong potential for advanced applications, including high‐resolution imaging, dynamic holography, optical tweezers, optical machining, and beyond.