Light scattering at a temporal boundary in a Lorentz medium

Temporal discontinuity in the permittivity of a nondispersive dielectric (temporal boundary) is a conventional model for considering electromagnetic phenomena in dynamic materials and metamaterials. Here we apply a more general model of a Lorentz medium with the rapidly changing density of its structural elements (oscillators) or their resonant frequency to determine the realms of applicability of the conventional temporal boundary model. We demonstrate the dependence of the continuity conditions and the energy relations at a temporal boundary on the nonstationarity mechanism and the ratio between the rate of nonstationarity and the characteristic frequencies in the system. (C) 2021 Optical Society of America

Automated summary

By utilizing a more general Lorentz medium model, this study investigates the realms of applicability of the traditional temporal boundary model in different scenarios, revealing a dependency of continuity conditions and energy relations on the nonstationarity mechanism and the ratio between the rate of nonstationarity and characteristic frequencies in the system.