Multiple scattering suppression in dynamic light scattering based on a digital camera detection scheme

TL;DR

This paper presents a CCD camera-based detection scheme in dynamic light scattering that effectively suppresses multiple scattering, enabling accurate measurement of single-scattered light in turbid samples with real-time analysis.

Contribution

The authors introduce a novel CCD camera detection method combined with cross correlation analysis to suppress multiple scattering in dynamic light scattering experiments.

Findings

Effective multiple scattering suppression up to $ ext{cm}^{-1}$ scattering coefficient.

Real-time analysis with temporal resolution of 0.2 seconds.

Valid for samples with low-order scattering, demonstrated on titanium dioxide suspensions.

Abstract

We introduce a charge coupled device (CCD) camera based detection scheme in dynamic light scattering that provides information on the single-scattered auto-correlation function even for fairly turbid samples. It is based on the single focused laser beam geometry combined with the selective cross correlation analysis of the scattered light intensity. Using a CCD camera as a multispeckle detector we show how spatial correlations in the intensity pattern can be linked to single and multiple scattering processes. Multiple scattering suppression is then achieved by an efficient cross correlation algorithm working in real time with a temporal resolution down to 0.2 seconds. Our approach allows access to the extensive range of systems that show low-order scattering by selective detection of the singly scattered light. Model experiments on slowly relaxing suspensions of titanium dioxide in glycerol were carried out to establish the validity range of our approach. Successful application of the method is demonstrated up to a scattering coefficient of more than $\mu_s = 5$ cm$^{-1}$ for the sample size of L=1 cm.