Dr. Arnulf Materny is a professor of Chemical Physics at Jacobs University Bremen since 2001. His field of specialization is the application and the development of laser spectroscopic techniques in the energy and time domain. Since 30 years Prof. Materny and his research group have been working with Raman spectroscopy and for 25 years they have performed experiments using femtosecond time-resolved laser spectroscopy. While the time-resolved work concentrates more on fundamental research topics, Raman spectroscopy is of considerable interest also for applications and industry collaboration. Therefore, in the recent years, the Materny group has applied Raman spectroscopy in different industry projects.
What is Raman spectroscopy? When light is scattered from objects, part of the scattering occurs inelastically, i.e. the wavelength of the scattered light is changed (“Raman scattering”). This is due to the interaction of the light with the molecules, which can be excited by the scattering process into excited vibrational states. The energy of the different molecular vibrations is missing in the scattered light and thus the resulting Raman spectrum reflects the internal molecular vibration energies. Since these energies are characteristic for the specific molecules, the Raman spectra can be considered to be molecular “fingerprints”, which can be used for analysis. Additionally, structural or chemical changes of the molecules and/or their environment can be detected from the Raman spectra. In contrary to infrared absorption spectroscopy, which yields similar information, for Raman spectroscopy no sample preparation is needed. Opaque samples as well as samples in aqueous solution can be studied without problem. Different Raman techniques are available. Raman-microscopy offers the possibility to investigate samples with high resolution. The variation of the excitation wavelength (laser wavelength) allows for resonance excitation of certain molecular species as well as for the avoidance of fluorescence, which yields unwanted background in Raman spectroscopy. Due to its properties, Raman spectroscopy can be performed using handheld systems or with setups included into production lines.
The Materny group has applied Raman spectroscopy to investigate polymers (e.g. micro-plastics contamination in sea water, structural properties of new types of plastics, plastic foils used for roofs of big sports stadia, etc.), textiles (e.g. silver-coated fabrics), food (e.g. plant oils, coffee, tea, etc.), explosives and chemical warfare agents (under water), and other materials.
Raman spectroscopy is also the link between Prof. Materny and Prof. Jiming Hu from Wuhan University. They know each other already for more than 25 years (University of Würzburg). Since then, they had met each other in China and Germany regularly. They also have exchanged young researchers and published several scientific papers in international journals. Also in 2017, Prof. Hu has visited the Materny group at Jacobs University Bremen. Prof. Hu is the director of the Institute of Analytical Biomedicine at and applies Raman spectroscopic techniques for the investigation of biological and medical samples. At Jacobs University Raman studies of e.g. skin-cancer cells using micro-Raman spectroscopy have also been performed.