All-Dielectric Metalattice with Enhanced Toroidal Dipole Response

摘要

A novel type of all-dielectric metalattice is proposed and experimentallyrndemonstrated, which supports broadband dominant toroidal dipole response.rnThe unit cell consists of four rectangular bars made of dielectric materialsrnof moderate contrast. By performing multipole decomposition it is foundrnthat toroidal dipole response is dominant over a wide frequency range. Therncorrelation between the toroidal dipole response and longitudinal electricrnfield component is also shown. By using this feature, as well as direct nearfieldrnmapping, the broadband toroidal dipole response of such metalatticernis experimentally verified. Since the unit cell exhibits C_4 rotational symmetryrnthis response is shown to be polarization independent.