Figure 6.

(a) Left: schematic image of the perfect absorption structure realized by coupling graphene with 1D PMMA grating. Middle: SEM image of a fabricated structure, the scale bar equals 5 μm. Right: measured (solid line) and simulated (dashed line) absorption spectra of structures with different grating periods under normal incidence of a white light source with TE polarization [64]. (b) Left: schematic image of the perfect absorption structure realized by coupling graphene with 2D subwavelength grating. Middle: measured (dot line) and simulated (dashed line) spectra of a fabricated perfect absorption structure. Right: measured (dot line) and simulated (dashed line) spectra of a resonant structure without graphene [65]. Reproduced from references [64,65], with permission from Wiley, 2016; with permission from Optical Society of America, 2017.