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Shedding Some Light – The Research Group “Applied Analytical Photonics” is testing novel technology under real-life conditions

Optical fibers at innoFSPEC. Photo: Roland Hass.

Optical fibers at innoFSPEC. Photo: Roland Hass.

Industry contacts are very important for the chemist Roland Hass and his research group Applied Analytical Photonics, which is working on Photon Density Wave (PDW) spectroscopy. A key advantage of this method is that it can analyze complex disperse materials such as wall paints, lotions, and milk during their manufacturing process. Analyzing these processes on-site is highly profitable for both parties.

Optical fibers are waveguides and are primarily used to transport light. By using optical fibers, light can be "bent around the corner", for example. There are different types of fibers with different properties, such as the ability to integrate optical elements with filter functions, bundle several fibers or split a single fiber into multiple ones. Astrophysicists of the Leibniz Institute for Astrophysics Potsdam (AIP), for example, use fiber-based light filters to suppress night sky emissions during terrestrial astronomical observations. They investigate how such filter lines can be incorporated into integrated optical components. Physical chemists at the University of Potsdam, in turn, use optical fibers to guide laser light into a chemical reactor. Such joint projects paved the way for the founding of innoFSPEC, the Center for Innovation Competence at the University of Potsdam and the Leibniz Institute for Astrophysics Potsdam (AIP). 

Analyzing biological processes in real time

Initially, innoFSPEC was supposed to create synergies between the quite different disciplines of physical chemistry, astrophysics, and astrophotonics, focusing on basic research. Later, researchers concentrated on examining the ideas, concepts, and technologies they had developed for their application potential. With currently seven different research groups, innoFSPEC now covers the entire spectrum from basic and application-oriented research and development to transfer projects and spin-offs.

The research group Applied Analytical Photonics (AAP) particularly focuses on these aspects. The research group’s leader Roland Hass studied and earned his doctorate at the University of Potsdam. The chemist already dealt with the further development of PDW spectroscopy in his dissertation. He then switched to the private sector before he prevailed in an international selection process for the leadership of the research group AAP.

Roland Hass and his team focus on the research and development as well as the practical applicability of this innovative technology and its use in process analytics as well as the development and combination of further fiber optic components for spectroscopy and sensor technology. One of the goals is to achieve better spatial resolution in highly concentrated, large-scale industrial processes. The scientists are working on testing the technologies they have developed under real-life conditions. Their contacts with partners in the food, pharmaceutical, polymer, and cosmetics industries are helpful for this purpose.

The group’s success is also due to the effective and modern instruments at its disposal, which include novel methods such as PDW spectroscopy and other measuring techniques for process analytics of liquid dispersions. The particular advantage of PDW spectroscopy is that it can be applied for highly concentrated, very turbid liquid dispersions, such as wall paints, skin lotions, milk, or substitute food. This technology allows inline measurements of particle sizes in the nanometer and micrometer range. During the production of adhesives, for example, the researchers can observe the growth of nanoparticles during the addition of monomers directly in the reactor. Monomers are molecules that combine to form polymers. Biomass growth can also be observed inline in biotechnological processes, such as the fermentation of yeast. If such analyses can be carried out already during the manufacturing process, one can avert the production of defective goods and better manage the quality of production processes.

The industry is very interested in cooperation

Liquids exhibiting extremely high turbidities are difficult to characterize optically since at least the absorption and scattering of light in them occurs in parallel. “As far as we know, we have developed a globally unique method that allows for these highly scattering and absorbing systems to be characterized during their processing,” Hass says. The research group now wants to establish this method as an analytical technology. For example, when enzymes are added to milk during cheese making, PDW spectroscopy is able to determine which structural changes take place as function of processing time. Normally, one would need to take a sample, pretreat it, cool it if necessary, dilute it, and then place it in an analyzer -- a time-consuming process. Due to this time delay, the process can no longer be correctly characterized.

“The new method provides real-time information during the processing and at very high concentrations,” the chemist explains. The industry is extremely interested in these high concentrations because they allow for a comparatively high yield in a short time. “The industry, food companies, breweries, the polymer industry prick their ears when they hear about the possibility of monitoring such processes.” This is why Roland Hass and his team repeatedly receive offers for research collaborations with national and international industry partners. The group has mobile devices with which they implement the technology into the companies’ facilities on-site and test them in measurement campaigns under real-life conditions.

In order to transfer the potential of this technology even more effectively, Dr. Roland Hass, Dr. Oliver Reich, and Prof. Dr. Hans-Gerd Löhmannsröben founded the company PDW Analytics GmbH in 2013, a spin-off of innoFSPEC. “This provides a significant increase in knowledge transfer to Golm, which greatly enhances our research,” Hass says. It will also enrich the technology campus of GO:UP. In cooperation with the Fraunhofer Institute for Applied Polymer Research and local companies, innoFSPEC creates joint labs here.

Fermentation in biology and biotechnology refers to the microbial or enzymatic conversion of organic substances into acid, gas or alcohol.

The Research Group Applied Analytical Photonics focuses on the development and fusion of fiber-optical photonic components for spectroscopy and sensor technology. One of AAP’s goals is the evaluation and implementation of new fiber-optical as well as photonic components for PDW spectroscopy. A particular focus is on probe-based multiplexing, which enables the spatial resolution of large-scale production processes. Due to the purely fiber-optical based probe technology, PDW spectroscopy leads, for the first time, to the characterization of processes, even in technically challenging process environments.



Applied Analytical Photonics (AAP)
Funding: Federal Ministry of Education and Research (BMBF)
Duration: 2016–2021



Dr. Roland Hass studied chemistry at the University of Potsdam. He is now head of the research group Applied Analytical Photonics at the Center for Innovation Competence innoFSPEC at the University of Potsdam. Together with Dr. Oliver Reich, he manages the company PDW Analytics GmbH.

Text: Dr. Barbara Eckardt
Translation: Susanne Voigt
Published Online by: Marieke Bäumer
Contact to the online editorial office: onlineredaktion@uni-potsdam.nomorespam.de