Fig. 1. Amorphous silicon nano cylinder cluster metasurface. (a) Schematic of amorphous silicon nano cylinder cluster metasurface; (b) refractive index and extinction coefficient of amorphous silicon

Fig. 2. Scattering cross section of amorphous silicon nano cylinder cluster metasurface

Fig. 3. Effective polarizabilities of amorphous silicon nano cylinder cluster metasurface, where periods are D_x＝D_y＝400 nm. (a) Imaginary parts of effective polarizabilities; (b) real parts of effective polarizabilities

Fig. 4. Simulation spectra of amorphous silicon nano cylinder cluster metasurface

Fig. 5. Simulated displacement currents and electric field distributions in x-y plane and x-z plane at resonant wavelengths of amorphous silicon nano cylinder cluster metasurface [Figs. 5(a) and 5(b) are respectively captured at the dotted line positions in Figs. 5(c) and 5(d)]. (a) In x-y plane at 654 nm; (b) in x-y plane at 667 nm; (c) in x-z plane at 654 nm; (d) in x-z plane at 667 nm

Fig. 6. Optical spectra of amorphous silicon nano cylinder cluster metasurface with varied incident angle, where D_x＝400 nm, D_y＝400 nm, r₁＝80 nm, r₂＝63 nm, d₁＝90 nm, and d₂＝80 nm. (a) Transmission spectrum; (b) reflection spectrum; (c) absorption spectrum