Pump-Wavelength\nSelective All-Optical Terahertz Metasurface\nwith Independent Amplitude and Frequency Modulations

Tunable terahertz (THz) metasurfaces based on optical\ncontrol are\ncrucial in high-speed communication, nondestructive testing, and imaging.\nHowever, realizing independent optical tunability of multiple functions\nin the THz band remains challenging due to limitations in control\nmaterials. Here, we experimentally demonstrate a novel THz metasurface\nthat employs two control materials combined with an electric-field-coupled\ninductor capacitor microstructure to achieve all-optical independent\nmodulations of amplitude and frequency. Amplitude modulation is achieved\nthrough near-infrared optical pumping, reaching a maximum modulation\ndepth of 94.42%. Broadband frequency modulation, spanning 0.21 THz,\nis accomplished using visible light pumping. The independent modulation\nfunction is owing to the odd-order nonlinear polarization characteristics\nof perovskite and the selective photon transition between the bottom\nSi island and the perovskite film. This work introduces a novel approach\nfor all-optical independent modulation of THz devices, offering valuable\ninsights for developing all-optical metasurfaces, intelligent light\nwindows, and multidimensional ultrafast switches.