Figure 5
From: Giant intrinsic chiro-optical activity in planar dielectric nanostructures
Far-field angular radiation patterns (|Ex|2). (a–d, Top) 3D far-field angular radiation patterns and (a–d, bottom) their 2D projections for the a electric dipole (E11), (b) magnetic dipole (M11), (c) magnetic octupole (M31) and (d) toroidal quadrupole (T21), respectively. For clarity, only the forward radiation direction (z≤0 half-space) is shown. The subscripts denote the corresponding spherical harmonic, Ylm, used to calculate the electric field. Here, the m=+1 harmonic is chosen as it is the dominant contribution to radiation along the z-direction, corresponding to zeroth-order transmission from the structure. Each point on the 2D projections obeys kx2+ky2+kz2=k02 (k0=2π/λ is the wavevector), which defines the radiation direction, and the magnitude is given by the color bar. The black lines demarcate where kz=0, that is, the radiation only occurs in the x–y plane.
