Efficient Light Funneling based on the non-Hermitian Skin Effect

TL;DR

This paper demonstrates how the non-Hermitian skin effect in anisotropic photonic lattices can be exploited to create highly efficient light funneling, with all modes localizing at an interface, surpassing Hermitian system expectations.

Contribution

It introduces the experimental realization of the non-Hermitian skin effect in photonic lattices, enabling efficient light funneling through mode localization at an interface.

Findings

All modes localize at the interface due to the skin effect.

Light is transported efficiently to the interface regardless of excitation.

The effect surpasses Hermitian system behavior in mode localization.

Abstract

In the last two decades, the ubiquitous effect of dissipation has proven to entail astonishing non-Hermitian features, rather than just being an inescapable nuisance. As an alternative route to non-Hermiticity, we tailor the anisotropy of a lattice, which constitutes an, up to now, barely exploited degree of freedom. In this case, the appearance of an interface dramatically alters the entire eigenmode spectrum, leading to the exponential localization of all modes at the interface, which goes beyond the expectations for Hermitian systems. This effect is dubbed "non-Hermitian skin effect". We experimentally demonstrate it by studying the propagation of light in a large scale photonic mesh lattice. For arbitrary excitations, we find that light is always transported to the interface, realizing a highly efficient funnel for light.