Figure 2: Numerical simulations of optical properties of SBRs.
From: Split-ball resonator as a three-dimensional analogue of planar split-rings
(a) Total scattering efficiencies of an SBR formed by a 200 nm gold sphere with a 50 nm wide by 100 nm deep cut. The SBR is excited by a plane wave directed from top antiparallel to z axis (solid curves) or from the side facing the cut along y axis (dashed curves). Polarization of the incident light is perpendicular or parallel to the cut. The black dotted curve represents scattering efficiency of the same particle without a cut. The grey curve is the absorption efficiency of the SBR for top excitation with polarization perpendicular to the cut. Inset is the schematic illustration of the SBR and directions of the incident plane waves. (b–e) Distributions of electric (b,d) and magnetic (c,e) field around the SBR at electric (b,c) (622 nm, polarization is parallel to the cut) and LC (d,e) (882 nm, polarization is perpendicular to the cut) resonance wavelengths. (f–i) Decomposition of the scattered field of SBR into multipole moments based on the vector spherical harmonics. SBR is excited from the top (f,g) or from the side facing the nanocut (h,i). Incident light polarization is perpendicular (f,h) or parallel (g,i) to the cut. All the electric and magnetic spherical multipole harmonics of the first and the second order are calculated and plotted in the figure. Only harmonics that have a noticable contribution are marked by corresponding coefficients (b10-magnetic dipole, a10 and a11-electric dipoles). a11 in all plots stays for a sum of a11 and a1-1 mode contributions.
