Abstract:We demonstrate successful terahertz (THz) wave manipulation using dielectric metasurfaces. By employing optical pumping at different wavelengths, the metasurface modulates THz waves in either mode-selective or non-selective manners. Distinct transmission relaxation processes are observed when varying the excitation photon energy, reflecting the band characteristics of silicon. Furthermore, we reveal an alternative optical control strategy through active adjustment of the pump-probe delay stage, enabling continuous tuning of THz polarization states via metasurface functionality control. We also offer according physical explanations. Our study proves that optical pumping serves as an effective external approach for dynamic THz wave manipulation, facilitating the development of versatile metasurface-based devices.