Role of Static Modes in Quasinormal Modes Expansions: When and How to Take Them into Account?
The scattering of electromagnetic waves by a resonator is determined by the excitation of the eigenmodes of the system. In the case of open resonators made of absorbing materials, the system is non-Hermitian, and the eigenmodes are quasinormal modes. Among the whole set of quasinormal modes, static...
| Hauptverfasser: | , |
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| Format: | Artikel |
| Sprache: | English |
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MDPI AG
2022-09-01
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| Schriftenreihe: | Mathematics |
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| Online Zugang: | https://www.mdpi.com/2227-7390/10/19/3542 |
| Zusammenfassung: | The scattering of electromagnetic waves by a resonator is determined by the excitation of the eigenmodes of the system. In the case of open resonators made of absorbing materials, the system is non-Hermitian, and the eigenmodes are quasinormal modes. Among the whole set of quasinormal modes, static modes (modes with a zero eigenfrequency) occupy a specific place. We study the role of static modes in quasinormal modes expansions calculated with a numerical solver implemented with the finite-element method. We show that, in the case of a dielectric permittivity described by a Lorentz model, static modes markedly contribute to the electromagnetic field reconstruction but are incorrectly calculated with a solver designed to compute modes with non-zero eigenfrequencies. We propose to solve this issue by adding to the solver a separate, specific computation of the static modes. |
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| ISSN: | 2227-7390 |