Resolving transitions in the mesoscale domain configuration in VO$_2$ using laser speckle pattern analysis

TL;DR

This paper introduces a novel laser speckle pattern analysis technique that provides rapid, mesoscale spatial and temporal insights into domain formation and evolution in VO$_2$, bridging the gap between existing spatially resolved and spectroscopic methods.

Contribution

The authors develop a new experimental approach that combines spatial and temporal resolution to study mesoscale domain dynamics in phase transition materials like VO$_2$.

Findings

Enables real-time mesoscale domain imaging.

Faster than traditional spatially resolved methods.

Applicable to other phase-separated systems.

Abstract

The configuration and evolution of coexisting mesoscopic domains with contrasting material properties are critical in creating novel functionality through emergent physical properties. However, current approaches that map the domain structure involve either spatially resolved but protracted scanning probe experiments without real time information on the domain evolution, or time resolved spectroscopic experiments lacking domain-scale spatial resolution. We demonstrate an elegant experimental technique that bridges these local and global methods, giving access to mesoscale information on domain formation and evolution at time scales orders of magnitude faster than current spatially resolved approaches. Our straightforward analysis of laser speckle patterns across the first order phase transition of VO$_2$ can be generalized to other systems with large scale phase separation and has potential as a powerful method with both spatial and temporal resolution to study phase separation in complex materials.