Abstract-Tunable plasmonic toroidal terahertz metamodulator

Burak Gerislioglu, Arash Ahmadivand, and Nezih Pala

https://journals.aps.org/prb/accepted/a007fO69A30E071822288ce861d87db2c9e4e9c5c

Optical modulators are essential and strategic parts of micro and nanophotonic circuits to encode electro-optical signals to the optical domain. Here, by using arrays of multipixel toroidal plasmonic terahertz (THz) metamolecules, we developed a functional plasmonic metamodulator with high efficiency and tunability. Technically, the dynamic toroidal dipole induces nonradiating charge-current arrangements leading to have exquisite role in defining the inherent spectral features of various materials. By categorizing in a different family of multipoles far from traditional electromagnetic multipoles, the toroidal dipole corresponds to poloidal currents flowing on the surface of a closed-loop torus. Utilizing the sensitivity of the optically driven toroidal momentum to the incident THz beam power, and by employing both numerical tools and experimental analysis, we systematically studied the spectral response of the proposed THz plasmonic metadevice. In this study, we uncover a correlation between the existence and excitation of toroidal response and the incident beam power. This mechanism is employed to develop THz toroidal metamodulators with strong potential to be employed for practical advanced and next-generation communication, filtering, and routing applications