Fig. 1. Multilayer thin-film optical structure and related parameters

Fig. 2. Reflectance, transmission, and absorption spectra of the multilayer thin-film structure

Fig. 3. Absorption spectra and electric field intensity distribution. (a) Light absorption spectra of monolayer graphene with/without the multilayer thin-film structure; (b) electric intensity field distribution of the multilayer structure; (c) intensity profile of electric field along the x-axis direction

Fig. 4. Graphene absorptivity curves and electric field intensity distribution of multilayer film structure. (a) Curves of absorptivity and the period number N of Bragg grating with the incident wavelength of 1549 nm; (b) electric field intensity distribution of multilayer thin film structure with incident wavelength of 1549 nm and N=10

Fig. 5. Changes of light absorption of graphene with ds2. (a) Spectral evolution of graphene light absorption with ds2; (b) curve of graphene light absorptivity peak versus ds2 when N=6

Fig. 6. Graphene absorption spectra. (a) Absorption spectra of graphene with different incident angles θ; (b) curves of peak wavelength of graphene absorption versus θ; (c) light absorption spectra of graphene versus the thicknesses d1 of SiO2 layer; (d) curve of peak wavelength of graphene absorption versus d1

Fig. 7. Effect of graphene chemical potential on light absorption of multilayer films. (a) Light absorption spectra of multilayer film structure with chemical potential of 0.325 eV and 0.398 eV (The illustration is the variation curve of light absorptivity versus graphene chemical potential at 1549 nm); (b) light absorption ratio of multilayer films with graphene chemical potential of 0.325 eV and 0.398 eV