(a) Experimental (exp) and simulation (sim) transmission spectra of the single-layer metasurface with x-LP and y-LP incidences, respectively. (b) Simulative and (c) experimental x-LP transmission spectra of double-layer chiral metasurface with different film thicknesses when the THz polarizer is rotated at 0°. (d) Relationship between the resonance frequency and the film thickness.