Fig. 1. Schematic diagram of the structure design and principle of the metasurface.(a) Schematic diagram of structure parameters and materials of the metasurface; (b) optical micrograph of the prepared metasurface samples; (c) simulation results of transmission of resonator structures under different VO₂ conductivity values; (d) electric field distribution of the two modes

Fig. 2. Spectral response of the sample at different temperatures. (a) Terahertz transmission spectra of the samples measured at ambient temperatures of 20‒81 ℃; (b) variation of resonant frequency with temperature

Fig. 3. Measured terahertz transmission spectra of the metasurface at the same ambient temperature with different laser pump powers. (a) 50 °C; (b) 60 °C; (c) 62 °C; (d) 70 °C

Fig. 4. Schematic diagram of the optical path of the strong THz pump-THz detection experiment and THz wire grid detail diagram. (a) Schematic diagram of the optical path (BS: beam splitter; WG: wire grid; WP: Wollaston prism); (b) THz wire grid detail diagram

Fig. 5. Terahertz transmission spectra of the substrate under different intensities of terahertz field. (a) Time-domain diagram;(b) frequency domain diagram; (c) E/E₀ diagram

Fig. 6. Terahertz transmission spectra of the metasurface at the same ambient temperature and different terahertz field amplitudes.(a) 50 ℃; (b) 62 ℃; (c) 63 ℃; (d) 70 ℃