Genetic optimization Invents non-Hermitian potentials for Asymmetric Reflectivity

TL;DR

This paper introduces a genetic optimization approach to design non-Hermitian potentials in layered structures, enabling controllable asymmetric light reflection that varies with frequency, using realistic dielectric and gain-loss materials.

Contribution

It presents a novel genetic optimization method to create non-Hermitian potentials for tailored asymmetric reflectivity in layered optical structures.

Findings

Achieves unidirectional light reflection controllable by frequency.

Designs use realistic dielectric and gain-loss materials.

Provides a general strategy for on-demand light transport.

Abstract

We propose a general design strategy based on genetic optimization to realize asymmetric reflectivity in periodic and non-periodic planar structures containing dielectric and gain-loss layers. By means of an optimization algorithm, it is possible to design the imaginary (or real) part of the complex permittivity distribution from any given and arbitrary real (or imaginary) permittivity distribution, i.e to create non-Hermitian potentials intended to achieve on-demand light transport for a selected spectral range. Indeed, the asymmetric response of the obtained complex permittivity distribution is directly related to its area in the complex permittivity plane. In particular, unidirectional light reflection can be designed in such a way that it switches from left to right (or vice versa) depending on the operating frequency. Moreover, such controllable unidirectional reflectivity can be realized using a stack of dielectric layers while keeping the refractive index and gain-loss within realistic values.