A modal perspective on the transverse Anderson localization of light in disordered optical lattices

TL;DR

This paper presents a modal analysis approach to understanding transverse Anderson localization of light in disordered optical lattices, revealing how localization depends on lattice parameters and eigenmode properties.

Contribution

It introduces a modal framework for analyzing light localization in disordered lattices, providing insights into optimal design parameters for maximum localization.

Findings

Localization strength correlates with average mode width.

Optimal site width for maximum localization is about twice the wavelength.

Periodic revival phenomena are explained through modal analysis.

Abstract

We frame the transverse Anderson localization of light in a one-dimensional disordered optical lattice in the language of localized propagating eigenmodes. The modal analysis allows us to explore localization behavior of a disordered lattice independent of the properties of the external excitation. Various localization-related phenomena, such as the periodic revival of a propagating Anderson-localized beam are easily explained in modal language. We characterize the localization strength by the average width of the guided modes and carry out a detailed analysis of localization behavior as a function of the optical and geometrical parameters of the disordered lattice. We also show that in order to obtain a minimum average mode width, the average width of the individual random sites in the disordered lattice must be larger than the wavelength of the light by approximately a factor of two or more, and the optimum site width for the maximum localization depends on the design parameters of the disordered lattice.