The increasing importance of materials that contain nano- to micrometer-sized particles creates a strong demand for sensing their physical-chemical properties. Additionally, the incorporation as so-called process analytical technologies (PAT), that are able to monitor chemical or physical changes during the production process, is of great benefit. Photon density wave (PDW) spectroscopy has been successfully introduced as a fiber-optical sensing approach for the characterization of the absorption and scattering properties without any sampling or sample preparation. Based on the analysis of the propagation of intensity-modulated laser light in these multiply scattering materials, PDW spectroscopy can be used to determine the particle or droplet sizes and concentrations of the chemical constituents. Among fundamental investigations of polymer-based model samples, on-line and in-line applications in polymer and food industry are discussed.
BIOGRAPHY: Oliver Reich studied chemistry at the University of Erlangen-Nuremberg with a special focus on physical chemistry and chemical engineering. He acchieved his PhD for fiberoptical sensing approaches with Photon Density Wave(PDW) Spectrsoscopy in the physical chemistry group of Prof. Löhmannsröben at