Generalized Time-Varying Drude Model for Dispersive and Lossy Modulations

TL;DR

This paper introduces a comprehensive time-varying Drude model that accounts for dynamic carrier properties, revealing complex behaviors like temporal blurring and spectral reshaping, which enhance understanding and design of time-modulated photonic media.

Contribution

It generalizes the Drude model to include explicit time dependence of carrier parameters, providing new analytical tools for studying dispersive and lossy time-varying media.

Findings

Non-adiabatic modulations cause distinct temporal behaviors.

Time-dependent losses lead to spectral reshaping.

The model aids in designing and fitting experimental photonic systems.

Abstract

We develop a generalization of the time-varying Drude model, treating carrier density, effective mass, and collision rate as explicit functions of time. We derive expressions for polarization, susceptibility, displacement, and permittivity in different domains. Our analysis reveals that non-adiabatic modulations and time-dependent losses induce rich and distinct behaviors, leading to temporal blurring, selective gating and suppression, and low-frequency spectral reshaping. Besides underpinning and upgrading the current framework on photonics of time-varying media, this model may be useful in the design and fitting theoretical models with experimental realizations.