Figure 2. Metasurface structure with simulated amplitude and phase curves.

(a) Schematic of an amorphous silicon (α-Si) cylindrical nano-post on a fused silica substrate. (b) Top view of the meta-atoms on a hexagonal lattice showing geometrical parameters. (c) Schematic of the simulated structure. (d) Intensity transmission, and phase of the transmission coefficient at λ = 915 nm and (e) at λ = 1550 nm. The lattice constant is 360 nm for λ = 915 nm and 720 nm for the λ = 1550 nm structure. The α-Si layer is 718 nm thick in both cases.