Anisotropic programmable metasurfaces with individually controllable 2-bit elements

Programmable metasurfaces capable of manipulating electromagnetic (EM) waves in real time provide new opportunities for various exciting applications. However, most previous programmable metasurfaces only work in a single polarization mode and their elements are controlled in a whole or one-dimensional way, which limits functionality and adaptability to complex environments. Here, an anisotropic programmable metasurface with individually controllable elements is proposed to realize real-time and independent dual-polarized EM control in the two-dimension direction. The anisotropic metasurface element is designed using the ingenious cross-over resonant structure integrated with two sets of varactors to achieve 2-bit phase modulation in the respective polarization direction. As a demonstration, an anisotropic programmable metasurface prototype with 21 x 20 such elements is simulated, fabricated, and measured. Real-time beam scanning and vortex wave generation are verified respectively under two different polarized wave incidences, which indicates that the realized anisotropic programmable metasurface can achieve totally distinct functionalities for two orthogonal polarizations. Our work could push programmable metasurfaces one step closer towards more advanced information devices and complicated applications in communication and imaging. (c) 2024 Chinese Laser Press