What is static multiple light scattering (SMLS)?

Static multiple light scattering (SMLS) is an optical method to measure the stability of dispersion, which is characterized by fast analysis speed, simple operation, and non-destructiveness. When the sample is irradiated by light, photons are scattered to varying degrees by the suspended substances, and some scattered photons are detected by either the backward detector or the forward detector. In a stability analyzer that utilizes SMLS technology, an optical setup is commonly comprised of an LED source, a forward detector, and a backward detector. During measurement, the optical setup moves in the vertical direction along the sample cell to capture the subtle variations of transmitted and backscattered signals that characterize destabilization processes. Transmitted signal is hardly detected when the samples are opaque. In this situation, backscattered signal is applied for stability analysis. For clear samples, transmitted signal is allowed to be used. Signal variations are then applied for qualitative and quantitative stability analyses.