Pseudo-Anapole Mode Establishment in Planar THz Metamaterial

In this paper, we propose new kind nonradiating state appearing in high Q planar toroidal THz metamaterial. So-called pseudo-anapole regime arises when the trivial solution to the non-radiating state condition is met. Here, both toroidal and electric dipole intensities are suppressed at resonance frequency while their far-field zone intensities tend to zero. The proposed effect is quite different from well-known anapole regime that is established by the condition p =− ikT that leads to nonradiating state [1] . The fundamental difference of pseudo-anapole state is that suppression of both electric and toroidal multipoles providing an opportunity for study of higher order multipoles from different families. This effect has been confirmed both numerically and experimentally in terahertz frequency range.