Arbitrary independent wavefront shaping at dual frequency with an all-silicon metasurface

Conventional metasurfaces are inherently frequency-selective, limiting wavefront control to a single operating frequency. Achieving independent manipulation at multiple frequencies remains a significant challenge for expanding the capabilities of integrated optics. Here, we propose and demonstrate an all-silicon metasurface platform that enables arbitrary independent wavefront shaping at two distinct terahertz frequencies. Our design leverages meta-molecules that synergize geometric and propagation phases to decouple the phase profiles for each frequency under a single polarization. This work provides a versatile platform for spatial-domain multiplexing, paving the way for high-capacity communication and multifunctional terahertz photonic devices.