Reconfigurable Beam Deflector and Polarization Converter Using Optomechanical Metasurface

In this article, a novel optomechanical metasurface for manipulating reflective phase and polarization state of linearly polarized electromagnetic (EM) wave is proposed. The presented MS consists of an electric-LC (ELC) resonators printed on a low-loss flexible printed circuit (FPC) substrate, an air gap in the middle layer, and a metallic substrate on the back ground. The phase modulation is realized via tuning geometrical parameters of ELC, while polarization modulation is achieved by illuminating different power levels of incident EM waves to flexibly control the ratio of polarization conversion. In particular, the reconfigurable characteristics of the proposed metasurface resulting from magnetomechanical coupling are demonstrated and validated, respectively. As a proof of concept, a reconfigurable beam deflector and a reconfigurable polarization converter based on the proposed optomechanical metasurface are designed, fabricated, and measured. The results show that the proposed reconfigurable beam deflector achieves beam reflection of 34° within bandwidth (BW) from 27.84 to 28.43 GHz, and the reconfigurable polarization converter enables a linear-to-circular polarization conversion with a 3-dB BW from 26.36 to 28.32 GHz. In addition, two devices will correspondingly generate specular reflective beam and realize linear-to-cross polarization conversion when increasing the incident power of EM waves. We envision optomechanical metasurface proposed here to hold possibilities for beam pointing and message encryption applied in wireless and radar communication.