Figure 1.

(a) Schematic of the reflective metalens with the black and blue arrow lines represent the incident light and reflected light, respectively. (b) Side view of the unit cell. The reflective metalens consists of Si nanoblocks and an Au ground plane, with a SiO₂ spacer placed between them. The heights are h = 400 nm, h ₁ = 200 nm and h ₂ = 150 nm. (c) Top view of the unit cell with W = 132 nm, L = 600 nm and lattice constant P = 650 nm. The required phase is imparted by rotating the nanoblock with an angle θ.