Modulated 3D cross-correlation light scattering: improving turbid sample characterization

TL;DR

This paper introduces a modulated 3D cross-correlation technique for light scattering that significantly enhances the accuracy of characterizing turbid samples by reducing cross-talk and improving signal quality.

Contribution

The authors develop a temporally modulated 3D cross-correlation method that improves single scattering detection in turbid samples, surpassing previous techniques in robustness and signal clarity.

Findings

Four-fold increase in cross-correlation intercept

Enhanced measurement of scattering intensity in turbid samples

Improved accuracy in dynamic and angular-dependent scattering analysis

Abstract

Accurate characterization using static light scattering (SLS) and dynamic light scattering (DLS) methods mandates the measurement and analysis of singly-scattered light. In turbid samples, the suppression of multiple scattering is therefore required to obtain meaningful results. One powerful technique for achieving this, known as 3D cross-correlation, uses two simultaneous light scattering experiments performed at the same scattering vector on the same sample volume in order to extract only the single scattering information common to both. Here we present a significant improvement to this method in which the two scattering experiments are temporally separated by modulating the incident laser beams and gating the detector outputs at frequencies exceeding the timescale of the system dynamics. This robust modulation scheme eliminates cross-talk between the two beam- detector pairs and leads to a four-fold improvement in the cross-correlation intercept. We measure the dynamic and angular-dependent scattering intensity of turbid colloidal suspensions and exploit the improved signal quality of the modulated 3D cross-correlation DLS and SLS techniques.