High-Capacity Photonic THz OAM Communication System Based on Broadband Huygens' Metasurface

We experimentally demonstrate a high-capacity photonic THz OAM wireless communication system based on a broadband Huygens' transmissive metasurface. The metasurface is designed to multiplex two distinct OAM beams with l=+1 and l=-1 operating at 0.1 THz, which has the advantages of low profile, simplicity, and ease of fabrication. Both simulation and measurement results indicate that it generates OAM beams with high purity over a broad bandwidth of 20 GHz (90–110 GHz). Crosstalk lower than −27 dB between the OAM modes can be achieved. Using the metasurface for a free-space link at a 0.1 THz carrier frequency, we achieve a 112 Gbit/s 16 quadrature amplitude modulation (16-QAM) data transmission with bit-error rates below 3.8e-3. This work verifies the feasibility of metasurface for high-capacity THz OAM communications, meaning it may open new opportunities for future THz communications.