Fig. 1. Schematic of the graphene-based absorber. (a) Monolayer graphene covered on the top of the CWG with a DBR mirror. (b) Cross-section of the absorber for TE-polarized light at normal incidence.

Fig. 2. RCWA simulation result and theoretically calculated result of the absorption spectrum for TE polarization light at normal incidence.

Fig. 3. Electric field amplitude distributions of the graphene-based absorber for TE polarization under normal incidence at the (a) on-resonant wavelength of 1550.8 nm and (b) off-resonant wavelength of 1540 nm.

Fig. 4. Absorption spectra in the structure as a function of wavelength and gap G using RCWA. The remaining parameters are set to P=710  nm, W1=200  nm, W2=150  nm, tg=220  nm, and tb=270  nm.

Fig. 5. Absorption spectra of the structure as a function of wavelength for different grating thickness tg and slab thickness tb. P=710  nm, W1=200  nm, W2=150  nm, and G=25  nm, (a) tb=270  nm, (b) tg=220  nm.