Quasinormal modes of Floquet media slabs
Abstract
Exploiting non-Hermitian wave-matter interactions in time-modulated media to enable the dynamic control of electromagnetic waves requires advanced theoretical tools. In this article we bridge concepts from photonic quasinormal modes (QNMs) and time-varying metamaterials providing the foundation for designing dynamic optical devices with prescribed scattering properties. Establishing the QNM framework for slabs with time-periodic permittivity, and solving the associated nonlinear eigenvalue problem, allows us to derive the QNM expansion capturing the resonant features of the system. This reduced-order model enables highly efficient computation of scattered fields while revealing insight into how modulation couples to resonant modes, creating tailored gain-loss engineering. Our approach is validated through numerical experiments on time-modulated systems, and we design strategies to engineer tailored excitations selectively amplifying or suppressing specific modal contributions.
Keywords
Cite
@article{arxiv.2507.02784,
title = {Quasinormal modes of Floquet media slabs},
author = {Benjamin Vial and Richard V. Craster},
journal= {arXiv preprint arXiv:2507.02784},
year = {2025}
}