Fig. 1. (a) Schematic diagram of all-dielectric metasurface structure. (b) Unit cell diagram. (c) Schematic diagram of TDS test optical path. (d) Picture of the metasurface. (e) Optical microscope imaging diagram. (f) Scanning electron microscopy image at 45° tilting platform. (g) Schematic diagram of metasurface processing flow.

Fig. 2. (a) Transmission spectrum for different values of g. (b) Corresponding 2D contours (black dashed lines represent the linewidth of the resonance peak). (c) Results after Fano fitting. (d) Values of radiation Q factor and g corresponding to the resonance frequency ω0. (e) Relationship between Q factor and asymmetry parameter α (log-log scale).

Fig. 3. (a) Transmission spectrum of BIC mode and QBIC mode. (b) Multipole decomposition of the QBIC mode resonance. (c) Magnetic field distribution in the z direction and electric field distribution in the y direction under different g values.

Fig. 4. Impact on the transmission spectrum. (a) Period. (c) Hollow length. (e) Hollow width. Impact on Q value and FWHM. (b) Period. (d) Hollow length. (f) Hollow width.

Fig. 5. (a) Simulation structure diagram. (b) Transmission spectrum at different refractive indices. (c) Corresponding two-dimensional profile diagram. (d) Linear fitting plot of refractive index versus center frequency.

Fig. 6. (a) Transmission spectrum at different thicknesses of Auramine O thin films. (b) Fitting curve of film thickness and resonance frequency. (c)–(e) Two-dimensional profiles at different r values.

Fig. 7. (a) Preprocessing flowchart of the metasurface sample. (b) Comparison of simulated and experimental transmission spectrum without the sample. (c) Transmission spectrum corresponding to Auramine O solutions of different concentrations. (d) Fitting relationship between resonance frequency and concentration. Under different humidities: (e) transmission spectrum; (g) statistical chart. Under different temperatures: (f) transmission spectrum; (h) statistical chart.