Sharp Toroidal Resonances in Planar Terahertz Metasurfaces.

Gupta, Manoj; Savinov, Vassili; Xu, Ningning; Cong, Longqing; Dayal, Govind; Wang, Shuang; Zhang, Weili; Zheludev, Nikolay I et al. · Adv Mater · 2016

basic_science · Level V

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Abstract

A toroidal dipole in metasurfaces provides an alternate approach for the excitation of high-Q resonances. In contrast to conventional multipoles, the toroidal dipole interaction strength depends on the time derivative of the surrounding electric field. A characteristic feature of toroidal dipoles is tightly confined loops of oscillating magnetic field that curl around the fictitious arrow of the toroidal dipole vector.