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arXiv · 2406.07214

Robustness of perfect transmission resonances to asymmetric perturbation

Ioannis Kiorpelidis·Panayotis Kalozoumis·Georgios Theocharis·Vassos Achilleos·Fotios K. Diakonos·Vincent Pagneux
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Abstract

We investigate the impact of asymmetric perturbations on the perfect transmission resonances (PTRs) of one-dimensional finite periodic systems. With no perturbations, the scattering region consists of $N$ identical cells, and the transmission spectrum exhibits at least $N-1$ PTRs in each pass band of the Bloch dispersion of the unit cell. By introducing a perturbation, the periodic structure is broken, which \textit{a priori} results in the elimination of all PTRs. However, we demonstrate that PTRs can still arise under asymmetric perturbations when the unperturbed system possesses mirror symmetry, utilizing the $\mathcal{PT}$ symmetry of the unperturbed reflectionless eigenvalue problem. We also reveal an intriguing connection between two seemingly independent PTRs that lies in the symmetry of the unperturbed unit cell: If one PTR is preserved, then a dual one is necessarily also preserved. Our findings offer insights for the design of, for example, a robust antireflection setup at multiple wavelengths or all-optical diode devices.

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Ioannis Kiorpelidis, Panayotis Kalozoumis, Georgios Theocharis, Vassos Achilleos, Fotios K. Diakonos, Vincent Pagneux. 2025-01-27. Robustness of perfect transmission resonances to asymmetric perturbation. https://doi.org/10.1103/physreva.111.012218

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