Fig. 1. (a) Schematic of the sample used in the experiment. (b) A unit cell structure. (c) The photo of the manufactured top structure. (d) The photo of the manufactured bottom structure.

Fig. 2. Spectra of the PCR ranging from 0° to 90°.

Fig. 3. Electric field distribution on cracked cross meta-surface for incident y-polarized waves at (a) 0.893 THz, (e) 0.95 THz. Electric field distribution on cracked cross meta-surface for incident x-polarized waves at (b) 0.893 THz, (f) 0.95 THz. Surface current distribution on cracked cross meta-surface for incident y-polarized waves at (c) 0.893 THz, (g) 0.95 THz. Surface current distribution on cracked cross meta-surface for incident x-polarized waves at (d) 0.893 THz, (h) 0.95 THz.

Fig. 4. (a) Schematic diagram of magnetic field coupling conversion. (b) Scheme of the multiple reflection–transmission processes of polarization. (c) Magnetic field in the direction of x. (d) Magnetic field in the direction of y.

Fig. 5. (a) Schematic diagram of the THz-TDS test system. (b) Photo of THz-TDS test system. (c) Transmission when the THz wave is incident on the THz polarization converter in different polarization directions by experiment. (d) Comparison between the experiment and simulation.