All-optical diode action in asymmetric nonlinear photonic multilayers with perfect transmission resonances

TL;DR

This paper demonstrates a new all-optical diode using asymmetric nonlinear multilayers that achieve high unidirectional transmission and low reflection without external modulation, promising efficient optical isolation.

Contribution

It introduces a novel multilayer structure exhibiting perfect transmission resonances for unidirectional light propagation, enhancing optical diode performance without external pumping.

Findings

Achieved >92% transmittance in one direction and ~22% in the opposite.

Demonstrated tunability of diode operation by perturbing resonance conditions.

Compared favorably to photonic quasicrystal-based designs.

Abstract

Light propagation in asymmetric Kerr-nonlinear multilayers with perfect transmission resonances is theoretically investigated. It is found that hybrid Fabry-P\'erot/photonic-crystal structures of the type (BA)^k(AB)^k(AABB)^m exhibit both pronounced unidirectionality (due to strong spatial asymmetry of the resonant mode) and high transmission (due to the existence of a perfect transmission resonance). This results in nonlinear optical diode action with low reflection losses without need for a pumping beam or input pulse modulation. By slightly perturbing the perfect transmission resonance condition, the operating regime of the optical diode can be tuned, with a trade-off between minimizing the reflection losses and maximizing the frequency bandwidth where unidirectional transmission exists. Optical diode action is demonstrated in direct numerical simulation, showing >92% transmittance in one direction and about 22% in the other. The effect of perfect transmission resonance restoration induced by nonlinearity was observed analytically and numerically. The proposed geometry is shown to have advantages over previously reported designs based on photonic quasicrystals.