Applying QCLs for Enhanced Spectroscopic Analysis of Liquids

For spectroscopic applications, quantum cascade lasers (QCLs) provide coherent, polarized mid-IR radiation with spectral power densities in the 10- to 100-mW range. These properties are very different from those of thermal light sources. With QCLs, innovative sensing methods can be developed that have advantageous features compared to established Fourier transform infrared (FTIR) spectroscopy.

Bernhard Lendl presents new developments, mainly with regard to liquid sensing that uses direct detection techniques. On the topic of liquid phase absorption spectroscopy, Lendl introduces dual beam spectroscopy with balanced detection and provides the example of protein analysis. Using a Mach Zehnder interferometer, he demonstrates liquid phase dispersion spectroscopy and discusses aspects of quantification in relation to absorption spectroscopy. He talks about polarimetric attenuated total reflection (ATR) spectroscopy as a new strategy that could improve the long-term stability of ATR spectroscopy. Finally, Lendl discusses integrated waveguide technology along with enhanced sensing methods for detecting trace concentration of pollutants in water.

About the presenter
Bernhard Lendl, Ph.D., is head of the Process Analytics Group within the Institute of Chemical technologies and analytics at the Technical University of Vienna. The focus of his research is the development of novel analytical techniques based on molecular spectroscopy for use in quantitative and qualitative analysis. We concentrate on emerging new technologies such as mid-IR quantum cascade lasers, waveguide technologies, particle manipulation by ultrasound, as well as performing chemical reactions and separations in micro-fluidic systems. By combining these techniques, novel analytical methodologies for the measurement of gases, liquids and solids can be developed which improve current state of the art instrumentation. These systems can be used to solve analytical chemical measurement problems in different fields extending from environmental and process monitoring to applications in medical diagnostics and life sciences. He is a recipient of the Fritz Pregl Prize, awarded annually since 1931 to an Austrian scientist for distinguished achievements in chemistry by the Austrian Academy of Sciences.