Dynamic light scattering (DLS)—also referred to as quasi-elastic light scattering (QELS)—is a nondestructive, light-scattering technique for particle characterization of colloidal dispersions, biological solutions, and solutions of macromolecules. DLS has also been referred to in the literature as photon correlation spectroscopy (PCS), which is one of the DLS measurement methods such as frequency analysis and cross-correlation spectroscopy. It is often used for measuring average particle diameter and the broadness of the size distribution of submicron-sized particles that are dispersed in a liquid and are free from the influence of sedimentation. Compared to other light-scattering techniques, DLS can provide size information in the nanometer (nm) range, which is out of the primary range of static light scattering (e.g., laser diffraction). In addition, DLS can also provide information on the stability of suspensions/emulsions as it is highly sensitive to aggregation and to the behavior of suspensions/emulsions under different dispersing conditions.