Fig. 2. Simulated transmission spectra of meta-atoms in THz Janus metasurface.
a Schematic diagrams of the eight SSRRs in meta-atoms of M1-M8. b, c Simulated cross/co-polarized transmission spectra of M1-M4 under the normal incidence of x-polarized THz wave. The VO2 conductivities in the insulating and metallic states are set to be 1 × 103 S/m (b) and 5 × 105 S/m (c), respectively. The meta-atoms of M5-M8 have the same transmission amplitude as M1-M4. Hence, only the transmission spectra of M1-M4 are shown here. d Cross-polarized transmission phase of the eight meta-atoms under the forward incidence of x-polarized THz wave at 0.99 THz when VO2 is in the insulating state. Phase differences between adjacent meta-atoms are about π/4. The F/B ratio is defined as the ratio of the cross-transmission at forward incidence to that at backward incidence