32-State Liquid Crystal Programmable Metasurface for Terahertz Phase Manipulation

This letter presents a programmable metasurface utilizing liquid crystals (LC) for terahertz applications, featuring a multistate phase shifter. Unlike a reflective metal layer, metallic grating is used in the metasurface unit. Nematic liquid crystal material is filled between the grating and the resonant structure. The grating electrodes in the unit are segmented into five groups. The bias voltage applied to different gratings allows the deflection of the liquid crystal molecules in the corresponding regions. The encodings in the experiment represent the states of the five sets of electrodes. The 32 switchable encodings of the phase shifter are evaluated in the experiments. At 393.2 GHz, the phase of the reflected wave varies between 0 degrees and 235 degrees depending on the different encodings. This study introduces a practical approach for implementing multibit programmable metasurfaces, facilitating the construction of reconfigurable intelligent metasurfaces in the terahertz frequency bands. This manipulation method could also be applied to other LC-based metasurface devices.