Exploring Unconventional Features Of Light Dynamics In Aubrey-Andre-Harper Model Based Quasi-periodic Optical Lattices

TL;DR

This paper investigates light localization in a quasi-periodic Aubrey-Andre-Harper waveguide lattice, revealing how topological parameters and disorder influence localized states, with implications for photonic device design.

Contribution

It introduces a novel analysis of topological band structures in AAH-based lattices and demonstrates disorder-induced light localization due to topological protection.

Findings

Higher quasi-periodic modulation enhances light localization.

Localization depends on excitation position and topological parameters.

Off-diagonal disorder promotes localization via topological protection.

Abstract

We report an Aubrey-Andre-Harper (AAH) model based quasi-periodic lossless evanescently coupled waveguide lattice to study the unconventional physics of light localization. We present an exclusive methodical analysis of the band-topology of a tight-binding discrete lattice and accordingly study the modal characteristics to reveal the fact that a higher value of quasi-periodic modulation strength is imperative for observing a signature of fully localized light states having higher eigenenergy. This analytical concept has numerically been implemented in the proposed topological lattice to achieve light localization, where we have shown that the supported states not only depend on topological parameters, but also on the specific location of excitation which is supported by the violation of bulk-edge correspondence due to quasi-periodicity. Furthermore, we have investigated a unique effect of the presence of disorder on light localization phenomenon, where it has been reported that the presence of off-diagonal disorder, which is otherwise detrimental, favours light localization in the proposed structure due to topological protection. The findings indeed have the potential to open up a fertile platform to manipulate light in topologically aided passive photonic devices.