Robust unidirectional transport in a one-dimensional metacrystal with long-range hopping

TL;DR

This paper demonstrates that one-dimensional metacrystals with long-range hopping can support robust, unidirectional light transport immune to disorder, without relying on topological protection or adiabatic pumping.

Contribution

It introduces a new mechanism for robust one-way transport in 1D systems using long-range hopping in metacrystals, bypassing the need for topological protection.

Findings

Unidirectional transport occurs in 1D metacrystals with long-range hopping.

Transport is immune to disorder and backscattering.

Implementation in optical systems using phase gratings is feasible.

Abstract

In two- and three-dimensional structures, topologically-protected chiral edge modes offer a powerful mean to realize robust light transport. However, little attention has been paid so far to robust one-way transport in one-dimensional systems. Here it is shown that unidirectional transport, which is immune to disorder and backscattering, can occur in certain one-dimensional metacrystals with long-range hopping without resorting to topological protection. Such metacrystals are described by an effective Hermitian Hamiltonian with broken time reversal symmetry, and transport does not require adiabatic (Thouless) pumping. A simple implementation in optics of such one-dimensional metacrystals, based on transverse light dynamics in a self-imaging optical cavity with phase gratings, is suggested