Fig. 3.

E-field confinement in the toroidal metamolecule. a, Cross-cut electric field enhancement (|E|²) as a function of position along x-axis, simulated for a unit cell at the toroidal dipole frequency, showing significant intensity of the confined fields at the capacitive openings in each resonator. b, 3D E-field enhancement map at the frequency of toroidal dipole, in which the strong field confinement was spotted at capacitive gap regions. The polarization and incident light direction are indicated inside the panel.