All-Dielectric Metalattice with Enhanced Toroidal Dipole Response

A novel type of all-dielectric metalattice is proposed and experimentally demonstrated, which supports broadband dominant toroidal dipole response. The unit cell consists of four rectangular bars made of dielectric materials of moderate contrast. By performing multipole decomposition it is found that toroidal dipole response is dominant over a wide frequency range. The correlation between the toroidal dipole response and longitudinal electric field component is also shown. By using this feature, as well as direct near-field mapping, the broadband toroidal dipole response of such metalattice is experimentally verified. Since the unit cell exhibits C-4 rotational symmetry this response is shown to be polarization independent.