Figure 1

Schematic of the geometry. (a) and (b) show the sample from opposite sides with F and B indicating the front and back side, respectively.Reuse & Permissions

Figure 2

Examples for simple anisotropic (a) and (b) and simple chiral (c) metaatoms. The structures are located in the $\mathit{xy}$ plane with light impinging normally to the structure in the $z$ direction. The black dashed lines indicate the mirror planes and the rotation axis, respectively. (a) Split-ring resonator with mirror plane parallel to the $y$ axis. (b) $\mathsf{L}$-shaped particle with identical arms with mirror plane ${45}^{°}$ inclined. (c) Cross on substrate with $C_4$ rotational symmetry with respect to the $z$ axis. The square-shaped substrate indicates the arrangement on a square lattice, necessary for the $C_4$ of the entire system. Such an arrangement gives rise to so-called structural chirality, although the particle itself is achiral.Reuse & Permissions

Figure 3

Examples for generalized anisotropic metaatoms. The metaatoms are located in the $\mathit{xy}$ plane with light impinging normally to the structure in the $z$ direction. The black dashed lines indicate the mirror planes in (a) and (b), and the black cross in (c) is a center of inversion symmetry. (a) A planar $\mathsf{L}$-shaped metaatom with different arms. (b) A planar $\mathsf{S}$-shaped metaatom with a $C_2$ symmetry with respect to the $z$ axis. (c) A three-dimensional metaatom made of $\mathsf{L}$-shaped particles with a center of inversion.Reuse & Permissions

Figure 4

Examples for generalized chiral metaatoms (a) and (b) and a no-symmetry metaatom (c). The structures are located in the $\mathit{xy}$ plane with light impinging normally to the structure in the $z$ direction. The black dashed lines indicate the axes of rotational symmetry in (a) and (b), which show three-dimensional structures made of two $\mathsf{L}$-shaped particles with $C_2$ symmetry with respect to the $x$ or $y$ axis, respectively. They are identical for forward and backward propagation. (c) A three-dimensional structure made of an $\mathsf{L}$-shaped particle and an $\mathsf{I}$-shaped particle with no symmetry at all.Reuse & Permissions