Nonreciprocal lensing and backscattering suppression via magneto-optical nonlocality

TL;DR

This paper presents a novel nonreciprocal electromagnetic response enabling backscattering suppression and directional lensing in topological photonics, demonstrated through spin spirals and metamaterials, advancing nonreciprocal optical device design.

Contribution

It introduces a new nonreciprocal response mechanism based on magneto-optical nonlocality, enabling backscattering suppression and directional lensing in photonic structures.

Findings

Backscattering is suppressed in the bulk of the structures.

Nonreciprocal lensing causes focusing from one direction and defocusing from the opposite.

Predictions are validated in spin spirals and metamaterials.

Abstract

We introduce a special kind of nonreciprocal electromagnetic response which gives rise to backscattering suppression in the bulk, a long-sought feature in topological photonics, as well as nonreciprocal lensing - an effect when the same structure focuses light incident from one direction and defocuses light propagating in the opposite way. We predict this response in spin spirals and in specially designed metamaterials, validating the key predictions.