DOCTORAL CANDIDATE 4

The DC 4 project is multidisciplinary: The work at IAF focuses on assembly, in-depth characterization and optimization of External Cavity Quantum Cascade Lasers (EC-QCLs) regarding the requirements of different measurement techniques to be developed in PROTEMIC. During the second stage at INSCL, the EC-QCL will be applied to study protein denaturation processes. The project is therefore best suited for candidates with a solid background in physics / photonics, who are also eager to cross the bridge to analytical chemistry and develop a good understanding of protein denaturation and its relation to mid-IR spectroscopy.

At IAF a flexible EC-QCL technology platform has been developed resulting in miniaturized and rugged EC-QCL modules. During the first stage of the project, dedicated EC-QCL modules for application in protein sensing will be realised. These EC-QCL sources will be optimized for direct (absorption, dispersion) and indirect (photothermal and photoacoustic) spectroscopy, respectively. In each case low noise operation, spectral repeatability and wavelength-dependent beam pointing instability will be investigated, and measures for improvement will be implemented. An EC-QCL unit dedicated to time resolved studies of indirect spectroscopies will be developed to provide maximum power in short pulses and at low repetition rates (~ 10-100Hz). DC4 will work with DC7 to adapt SpectroPlate for the EC-QCL. This laser will be used also by DC10 for microreactor measurements. DC4 will further assemble an EC-QCL(1500-1700 cm-1) for use in PT imaging (coop. with DC5) and on the study of protein denaturation processes when working at the co-host INSCL during the second state of the project. For the latter application small changes in the protein spectra need to be detected requiring utmost stability of the planned measurements. Difference spectra will be utilized for analysis, effectively eliminating drifts and matrix effects. A key objective is to engineer a versatile platform that continuously probes protein denaturation processes within a digestion reactor/chamber.