Beam splitting and power allocation for optical wireless communication with a polarization-multiplexed free-form metasurface

As a promising technology for sixth-generation (6 G) mobile networks, optical wireless communication (OWC) requires efficient beam separation for multi-user channel expansion and flexible power allocation for energy-efficient operation. Conventional beam-control components provide limited spatial-channel scalability and lack intrinsic capability for continuous inter-channel power allocation. Here, we propose a polarization-multiplexed free-form metasurface for efficient beam splitting and power allocation. Through inverse design, the metasurface routes p- and s-polarized components into separate diffraction orders, achieving an average measured diffraction efficiency of approximately 78% and channel isolation above 12 dB. Rotation of the incident polarization state continuously redistributes power between the two fixed beams without reconfiguring the metasurface. Link-level validation further demonstrates dual-channel transmission and adaptive power allocation under unequal channel conditions. This work provides a compact and energy-efficient route toward massive-access and green OWC systems in the future.