Metadisorder for designer light in random-walk systems

TL;DR

This paper introduces 'metadisorder', a novel approach to design eigenstates in highly-disordered wave systems, enabling ordered wave phenomena and new functionalities despite strong disorder.

Contribution

The authors propose and demonstrate 'metadisorder', allowing arbitrary molding of eigenstates in disordered systems, leading to ordered wave transport and innovative functionalities.

Findings

Ordered waves achieved in highly-disordered systems.

Counterintuitive functionalities like phase-controlled beam steering.

Disorder-induced phenomena such as 'small-world-like' transport.

Abstract

Disorder plays a critical role in signal transport, by controlling the correlation of systems. In wave physics, disordered potentials suppress wave transport due to their localized eigenstates from random-walk scattering. Although the variation of localization with tunable disorder has been intensively studied as a bridge between ordered and disordered media, the general trend of disorder-enhanced localization has remained unchanged, failing in envisaging the existence of delocalization in highly-disordered potentials. Here, we propose the concept of 'metadisorder': tunable random-walk systems having a designed eigenstate with unnatural localization. We demonstrate that one of the eigenstates in a randomly-coupled system can always be arbitrarily molded, regardless of the degree of disorder, by adjusting the self-energy of each element. Ordered waves are then achieved in highly-disordered systems, including planewaves and globally- collective resonances. We also devise counterintuitive functionalities in disordered systems, such as 'small-world-like' transport from non-Anderson-type localization, phase-conserving disorder, and phase-controlled beam steering.