Multiple scattering suppression in static light scattering by cross-correlation spectroscopy

Abstract

Cross-correlation techniques have been used successfully to suppress multiple scattering in dynamic light-scattering experiments on turbid samples. This allows dynamic information to be obtained straightforwardly by processing the remaining single scattering. Here we show that cross-correlation techniques can also be used to suppress multiple scattering in static light-scattering measurements. We use the two-color dynamic light-scattering method and exploit the fact that the amplitude of the time-dependent part of the measured intensity cross-correlation function depends on the ratio of the single-scattered intensity to the total (single + multiple) scattered intensity. The method is illustrated by measurements of the static structure factors of concentrated suspensions of "hard-sphere" colloids. Good agreement is found with those calculated in the Percus-Yevick approximation.

Investigation of Particle Interactions in Concentrated Colloidal Suspensions Using Frequency Domain Photon Migration: Monodisperse Systems

“…One proposed method to suppress multiple scattering employs cross-correlation techniques (11). Using a two color cross-correlation technique, Moussaid and Pusey (12) probed structure factors of colloidal suspensions with SALS measurements at high volume fraction (∼0.5). However, this approach is not stable and some adjustments are frequently necessary to maximize the amplitude of the cross-correlation.…”

Easy-use and low-cost fiber-based two-color dynamic light-scattering apparatus

“…The maximum intercept in the cross correlation of 0.4 is smaller than the one in the original setup described in Ref. [23] but is still twice as good as the ones in the 3DDLS setups. The intercept can be improved using high quality detectors, high quality low noise lasers, and ultrahigh precision ball bearings (radial tolerance ∼1 μm) constructing the four rotation stages.…”

“…The original scheme [29] was a masterpiece of engineering giving the possibility to reach a maximum intercept in the cross-correlation mode of √ β 1 β 2 β OV ≈ 0.8 close to the maximum possible value [23]. Unfortunately, it is a challenge to align this setup, and a long time stable alignment can only be achieved in a thermostated laboratory with absolute temperature changes lower than 1 • C.…”

“…Absolute structure factors of colloidal liquids and fluids with short range interaction determined with standard LS techniques always are subjected to error. Measurements of absolute structure factors are very rare [23,24], and, to the best of our knowledge, absolute structure factors of metastable colloidal fluids and melts with short range interaction only have been presented once [14].…”

Assessment of Small-Angle and Angle-Averaged Structure Factor for Monitoring Electrostatic Colloidal Interactions Using Multiply Scattered Light

“…In their work, they demonstrated that S(0) decreased with decreasing ionic strength and with increasing polystyrene volume fraction (14). Using cross-correlation techniques, the influence of multiple light scattering in static and dynamic measurements can be suppressed (15)(16)(17). However, in dense suspensions wherein the multiply scattered signal is predominant, cross-correlation techniques are not suitable owing to the small signal-to-noise ratio of the measurement.…”