Figure 5.

(a) Schematic illustration of coherent absorption in a nanostructured graphene, accompanied by the phase modulation of coherent absorption at the resonance wavelength of 8.476 µm [25]. (b) Left: schematic of a graphene ribbon meta-surface illustrated by two counter propagating and coherently modulated input beams. Right: The difference ($\left|\mathrm{r}\right|-\left|\mathrm{t}\right|$) of the scattering coefficients for the graphene meta-surface as functions of frequency and Fermi energy E_F, the solid blue line indicates quasi-CPA points where $\left|\mathrm{r}\right|=\left|\mathrm{t}\right|$ [126]. Reproduced from references [25,126], with permission from Optical Society of America, 2014; with permission from Nature Publishing Group, 2015.