[Zurück]

B. Lendl, J. Hayden, J.P. Waclawek, H. Moser, M. Montemurro, A. Schwaighofer:
"New Mid‐IR Laser Based Schemes for Gas and Liquid Sensing";
Hauptvortrag: International Conference on Advancing Molecular Spectroscopy (ICAMS), Nishinomiya Campus of Kwansei Gakuin University (eingeladen); 30.06.2018 - 01.07.2018.

Advances in Analytical Chemistry are often linked to technological developments in
neighboring disciplines. This also concerns the recent development of quantum cascade lasers,
which allows realization of sensing approaches in the mid-IR range that are different and
potentially more powerful compared to classical absorption measurements based on Lambert-
Beer law. In this presentation new approaches for gas and liquid sensing using quantum cascade
lasers will be presented and discussed.
In the field of trace gas sensing indirect methods such as photothermal and photoacoustic
techniques are very promising as the analytical signal is directly proportional to the analyte
concentration and the laser power. This presentation will focus on recent advances in
Photothermal Interferometry (PTI) and Quartz Enhanced Photoacoustic Spectroscopy
(QEPAS) employing distributed feedback Quantum Cascade Lasers. LODs in the single digit
ppb range for CO and SO2 have been achieved recently.
For liquid sensing external cavity Quantum Cascade Lasers (EC-QCL) are used. The latest
generation of these lasers finally allows to outperform state-of-the-art FTIR spectrometers. This
will be shown on the example of protein analysis in milk.
Finally, a Mach Zehnder interferometer for highly sensitive dispersion spectroscopy will be
introduced, again using an EC-QCL as light source. Focusing on the measurement of the
refractive index this novel set-up will report on quantitative sugar analysis.