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arXiv · 2605.19699

Resonant Electric-Magnetic Toroidal Duality in Height-Modulated Hexagonal Metasurfaces

Oleksiy Breslavets·Yuri Savin·Zoya Eremenko
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Abstract

Toroidal modes enable high-Q resonances, but electric toroidal excitations remain unexplored compared to magnetic ones. This work establishes electric-magnetic toroidal duality in a hexagonal metasurface. Using finite element simulations, we analyze electric and magnetic toroidal modes in a hexagonal silicon nanorod supercell under mirror-symmetry breaking via height modulation. Eigenfrequencies, Q-factors, power flow, and polarization responses are computed. We identify electric TO and ATO modes with complementary near-field topologies to magnetic analogues. Direct frequency intersections (magnetic and electric TO/ATO) yield high-Q quasi-BICs. Polarization selectivity reverses between families: 0{\deg} excites magnetic TO/electric ATO; 90{\deg} excites magnetic ATO/electric TO. A loss hierarchy (magnetic TO > magnetic ATO > electric ATO > electric TO) and protective layers compatibility are demonstrated. Electric and magnetic toroidal responses are dual manifestations of the same symmetry, providing a unified design framework for high Q metasurfaces in sensing, nonlinear optics, and loss-tolerant devices.

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Oleksiy Breslavets, Yuri Savin, Zoya Eremenko. 2026-05-19. Resonant Electric-Magnetic Toroidal Duality in Height-Modulated Hexagonal Metasurfaces. https://arxiv.org/abs/2605.19699

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