Fig. 2: Angular dispersions of a typical optical metasurface.

a Schematic of a perfect meta-absorber in the MIM configuration under illumination by TM-polarized light. b Top-view SEM image of the fabricated sample, with \(t_{(0,0)}^{(0,1)}\) denoting the coupling strength between the two meta-atoms labeled {0,0} and {0,1}. c Resonant frequency of the meta-absorber as a function of incident angle, obtained by experiments, FEM simulations and TBM calculations. d Damping parameters \(\Gamma _i\) and \(\Gamma _r\) of the meta-absorber as functions of the incident angle, retrieved from FEM simulations. e Measured and simulated reflectance spectra of the meta-absorber illuminated by TM-polarized light at different incident angles. The geometrical parameters of the meta-surface are P_x = 270 nm, P_y = 400 nm, L_x = 240 nm, L_y = 50 nm, t = 30nm, t_s = 45 nm and t_m = 150 nm