Tunable terahertz beam splitter based on programmable liquid crystal integrated metasurface

As a kind of essential functional device, beam splitters can separate beams into desired directions and divide energy into two or more portions, which can find critical applications in interferometry, communication link construction, and imaging. Here, we propose a programmable terahertz beam splitter based on liquid crystal and metasurface. This device combines the dual-channel beam deflection of a geometric-phase metasurface with the phase-shifting offered by a digital coding liquid crystal array consisting of 64 elements. By dynamically adjusting the energy distribution between the two deflection channels, the device can achieve splitting ratios ranging from 9:1 to 2:3 using five distinct coding sequences, while maintaining a constant deflection angle of ±24° at 1.1 THz. This work offers a valuable reference for the development of liquid crystal integrated functional devices for the terahertz band, with potential applications in terahertz optics and communications.