Figure 1 : Computational model.

From: Design of a structure with low incident and viewing angle dependence inspired by Morpho butterflies

Figure 1

(a) tree-like structure, incident light, reflected light, incident angle α, and viewing angle β; and (b) evolving the model from a multilayer to a tree-like structure by incorporating three parameters: ΔR (ridge width) = 60 nm, ΔT (lamella taper) = 10 nm, and ΔL (lamella distribution) = 0 nm, 100 nm, 0 nm, 100 nm, ….; (c) the boundary condition in the vertical direction is absorbing (perfectly matched layer, PML), and the boundary condition in the horizontal direction is periodic (periodic boundary condition, PBC).