Photon correlation spectroscopy – also referred to as dynamic light scattering – is a method of particle size measurement in which the light of a laser scattered by a sample is analyzed.
To determine the size of different particles in solutions or suspensions, it is best to use the layout shown in the schematic above. A laser beam hits a sample and is scattered by the particles at an angle. The scattered light is then detected by a single photon avalanche diode. The movement of the particles in relation to one another affects the intensity with time, and this is detected by the diode. These measurement values provide information about the speed of the individual particles and thus about their size. With the help of photon correlation spectroscopy, particle sizes can be determined in the submicron range, and oftentimes even in the nanometer range.
