Fig. 3
From: Planar metasurface-based concentrators for solar energy harvest: from theory to engineering
(a) High-level schematic of various of nanostructures to achieve phase control in metasurfaces. (b) Schematic of Mie resonant: an (infinite) array of nanodisks represented as electric and magnetic dipoles with polarizabilities αe and αm for x-polarized incident light. Electric (colored arrows) and magnetic (plain color-coded) field distributions of the magnetic (right-top) and electric (right-bottom) mode of a silicon (Si)-nanodisk metasurface. (c) Schematic designs and the results of full-wave simulations of the individual Babinet-inverted nanoantennas. The pseudo-color field map indicates the cross-polarized light scattered from each nano-antenna. (d) Photonic nanocavities using a two-dimensional (2D) photonic-crystal slab: (I) Starting cavity structure with three missing air rods (I) and designed cavity structure created by displacing the air rods at both edges (IV); (II and III) and (V and VI) Electric field profile and 2D Fourier transform spectrum, respectively, for the designed cavity shown in (I) and (IV). (e) Schematic of the Fourier meta-lens (I) and magnetic intensity distribution of the dielectric waveguide (II). Intensity distribution in the focal plane (III). (f) PB geometric phase variation of the co-polarization (solid lines) and cross-polarization (dashed lines) transmitted wave, as a function of the orientation angle of the unit cell. The inset shows a visualization of the PB phase on the Poincaré sphere. (a) Reproduced with permission [96]. Copyright 2019, Optical Society of America (OSA). (b) Reproduced with permission [97]. Copyright 2015, Wiley-VCH. (c) Reproduced with permission [98]. Copyright 2013, NPG. (d) Reproduced with permission [99]. Copyright 2003, NPG. (e) Reproduced with permission [100]. Copyright 2018, Wiley-VCH. (f) Reproduced with permission [69]. Copyright 2015, Wiley-VCH