Fig. 7
From: Planar metasurface-based concentrators for solar energy harvest: from theory to engineering
(a) Simulated focusing property from six distinct meta-lenses consisting of individual nanopillar arrays for red, green, and blue colors, respectively. Schematic of in-plane, on- (I) and off-axis (II) focusing meta-lens. Right side of (I) and (II): distribution of electric field intensity of the in-plane, on- and off-axis focusing meta-lens at the incident wavelengths of 430 nm (blue color map), 532 nm (green color map), and 633 nm (red color map). (b) (I) Schematic of a metasurface unit cell. (II) SEM image of the meta-lens. Left side of (III): Schematic of focusing. Right side of (III): Cross-focus cuts and intensity distributions in the focal plane. (a) Reproduced with permission [164]. Copyright 2017, ACS. (b) Reproduced with permission [142]. Copyright 2020, NPG