Fig. 1. (a) Schematic of graphene-integrated MDM-CHA. Thicknesses of the Al2O3, Al, GaAs spacer, and graphene are 3, 17, 10, and 0.5 nm, respectively. (b) Illustration of the chiral triad composed of wave vector (k), normal vector (n), rotation angle φ in the x−y plane, and different lattice vectors (a or b), marked in black. (c) Illustration of the rectangular lattice pattern of CHA, where Lx=1600  nm, Ly=1000  nm and r=310  nm. (d) Effective permittivity of graphene ϵeff for Fermi energies of graphene (EF) of 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, and 1.0 eV.

Fig. 2. Spectra of (a) t++ and t−−, (b) t−+, t+− and CCD of the achiral metasurface (Lx=1600  nm, Ly=1000  nm) integrated with the graphene sheet (EF=0.1  eV) under θ=45°, φ=15°. (c) CCD spectra for EF=0.4, 0.6, 0.8, and 1.0 eV under θ=45°, φ=15°. (d) Positions of CCD resonant dip as a function of EF at θ=45°, φ=15°.

Fig. 3. CCD spectra for the (a) different φ with θ=45°, (b) different θ with φ=15°, where Lx=1600  nm, Ly=1000  nm, and EF=0.1  eV. (c) 2D diagram of CCD against θ and φ at an operating wavelength of 1990 nm with a step of 1°. (d) CCD spectra for different Td at θ=45° and φ=15°. (e) CCD spectra for different TAl at θ=45° and φ=15°.

Fig. 4. Representation of the dispersion relation of the Al2O3/Al/GaAs/Al/Al2O3 multilayer (left column), and the CCD spectra of the CHA penetrating through the Al2O3/Al/GaAs/Al/Al2O3 multilayer at θ=45°, φ=15° (right column), where both of the structures are covered by a graphene film, respectively, for (a) EF=0.1  eV, (b) EF=0.4  eV, (c) EF=0.6  eV, (d) EF=0.8  eV, and (e) EF=1.0  eV.

Fig. 5. (a)–(f) Total time-averaged E-field distributions at the interface between the bottom Al2O3 layer and air during light propagation through the achiral metasurface at EF=0.1, 0.4, 0.6, 0.8, and 1.0 eV. The response to LCP and RCP incidence is displayed on the left and right, respectively. The incident total E-field has an amplitude of 1 V/m. The E-field distributions on the bottom Al2O3-air interface are normalized to the maximum intensity of the E-field at θ=φ=0°. (a) Total E-field distributions under the perpendicular incidence (θ=φ=0°), showing patterns with mirror symmetry for the two circular polarizations at λ=1990  nm and EF=0.1  eV. The asymmetric E-field distributions for oblique incidence (θ=45°, φ=15°) at (b) λ=1990  nm and EF=0.1  eV, (c) λ=1996  nm and EF=0.4  eV, (d) λ=2034  nm and EF=0.6  eV, (e) λ=2074  nm and EF=0.8  eV, and (f) λ=2124  nm and EF=1.0  eV.

Fig. 6. (a) C/CCPL spectra in the aperture (red spot in the left inset) for EF=0.1, 0.4, 0.6, 0.8, and 1.0 eV under an LCP incidence with θ=45°, φ=15°. Right inset shows a vertical cross section of the circular hole containing a chiral molecule. (b)–(f) Distributions of |E/E0|, |H/H0|, and C/CCPL at an interface between the bottom Al2O3 layer and air under an LCP incidence with θ=45°, φ=15° for (b) λ=1990  nm and EF=0.1  eV, (c) λ=1996  nm and EF=0.4  eV, (d) λ=2034  nm and EF=0.6  eV, (e) λ=2074  nm and EF=0.8  eV, and (f) λ=2124  nm and EF=1.0  eV.