Formulation of Dispersive and Dissipative Time-Varying Media as a Floquet Matrix Eigenproblem
Phys. Rev. Lett. 135, 156903 – Published 9 October, 2025
DOI: https://doi.org/10.1103/lcmw-qrrp
Abstract
Dispersion is ubiquitous in nature as a result of causality, and dispersive time-varying materials have been widely used in the experimental realization of photonic time-varying media. Here, we derive the Floquet Hamiltonian and formulate Maxwell’s equations of dispersive time-varying media as a Floquet matrix eigenproblem. The derived Floquet Hamiltonian allows us to investigate the band structures and eigenmodes of the system. Using the eigenmodes, we identify the Floquet exceptional points by tracking the variation of Aharonov-Anandan phase. Our theory rigorously reformulates existing models and facilitates the development of Floquet Green’s function and resonant mode expansion in open photonic time-varying systems.