Singularity displacement in random speckle patterns of diffusive and localized waves: universality lost and regained

TL;DR

This paper investigates how the movement of phase singularities in speckle patterns varies between diffusive and localized waves, revealing that universality can be restored when considering phase excursion, thus aiding in characterizing wave propagation.

Contribution

It demonstrates that phase singularity motion statistics differ between diffusive and localized waves and shows universality is regained through phase excursion analysis.

Findings

Phase singularity motion differs for diffusive and localized waves.

Universality is restored when analyzing phase excursion.

Speckle pattern evolution can monitor internal motion in complex systems.

Abstract

All random wave fields possess a network of phase singularities. We show that while the phase statistics within speckle patterns is generic, the statistics of the motion of phase singularities differs substantially for diffusive and localized waves. This reflects the changing wave interaction with the underlying modes of multiply-scattering systems. Universality is regained when the motion of phase singularities is charted against the phase excursion which reflects the variation of phase change across the speckle pattern. The evolution of speckle patterns can therefore be used to monitor internal motion in complex systems and to characterize the nature of wave propagation.