Polarization switching and nonreciprocity in symmetric and asymmetric magnetophotonic multilayers with nonlinear defect

TL;DR

This paper investigates how nonlinear defects in symmetric and asymmetric magnetophotonic multilayers induce polarization switching and nonreciprocity, with potential applications in optical isolators and polarization devices.

Contribution

It introduces a model of magnetophotonic multilayers with nonlinear defects, demonstrating polarization bistability and nonreciprocal effects due to spatial asymmetry and nonlinearity.

Findings

Demonstrated polarization bistability in the structure

Observed abrupt polarization switching between circular and elliptical states

Identified field localization at defect-mode resonances as the mechanism

Abstract

A one-dimensional magnetophotonic crystal with a nonlinear defect placed either symmetrically or asymmetrically inside the structure is considered. Simultaneous effects of time-reversal nonreciprocity and nonlinear spatial asymmetry in the structure are studied. Bistable response is demonstrated in a such system, accompanied by abrupt polarization switching between two circular or elliptical polarizations for transmitted and reflected waves. The effect is explained in terms of field localization at defect-mode spectral resonances and can be used in the design of thin-film optical isolators and polarization transformation devices.