Photon transport enhanced by transverse Anderson localization in disordered superlattices

TL;DR

This paper demonstrates how transverse Anderson localization in disordered superlattices can significantly enhance photon transport and collimation, revealing a transition from guided resonances to localized regimes at the chip scale.

Contribution

It introduces a new anisotropic photonic structure that leverages controlled disorder to induce transverse Anderson localization, advancing light control at subwavelength scales.

Findings

Diffraction is nearly arrested by cascaded resonant tunneling.

Disorder induces transverse localization with exponential mode profiles.

Enhanced collimation bandwidth observed with increasing disorder.

Abstract

One of the daunting challenges in optical physics is to accurately control the flow of light at the subwavelength scale, by patterning the optical medium one can design anisotropic media. The light transport can also be significantly affected by Anderson localization, namely the wave localization in a disordered medium, a ubiquitous phenomenon in wave physics. Here we report the photon transport and collimation enhanced by transverse Anderson localization in chip-scale dispersion engineered anisotropic media. We demonstrate a new type of anisotropic photonic structure in which diffraction is nearly completely arrested by cascaded resonant tunneling through transverse guided resonances. By perturbing the shape of more than 4,000 scatterers in these superlattices we add structural disordered in a controlled manner and uncover the mechanism of disorder-induced transverse localization at the chip-scale. Arrested spatial divergence is captured in the power-law scaling, along with exponential asymmetric mode profiles and enhanced collimation bandwidth for increasing disorder. With increasing disorder, we observe the crossover from cascaded guided resonances into the transverse localization regime, beyond the ballistic and diffusive transport of photons.