Hannover 2016 – scientific programme

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P: Fachverband Plasmaphysik

P 2: Plasma Diagnostics I

P 2.1: Invited Talk

Monday, February 29, 2016, 11:00–11:30, b305

Mid-infrared cavity enhanced absorption spectroscopy of gas and surface species — •Jean-Pierre van Helden, Norbert Lang, Andy Nave, and Jürgen Röpcke — Leibniz Institute for Plasma Science and Technology (INP Greifswald), Greifswald

Understanding how plasmas interact with solid and liquid surfaces is of central importance in many fields such as microelectronics, materials and surface processing and in environmental and biomedical technologies. Improving process efficiency requires a comprehensive understanding of the kinetics of the transient intermediates involved at the plasma-substrate interface. The experimental approaches currently available provide an incomplete picture of plasma-surface interactions due to relatively low sensitivity. A further increase in sensitivity to detection limits of ppm down to ppt levels can be achieved by combining quantum and interband cascade lasers (QCLs and ICLs) with cavity-enhanced techniques based on optical cavities. The surface species can be detected by combining EC-QCLs with evanescent-wave attenuated-total-reflection (EW-ATR) spectroscopy. Cavity enhanced absorption spectroscopy can also be combined with ATR measurements. It was recognized early on in the development of cavity enhanced spectroscopies that if the internal reflection element in which the evanescent-wave is generated in ATR is included in the cavity it would greatly enhance ATR sensitivity. Here, the latest results in the development and applications to plasmas of mid-infrared cavity enhanced absorption spectroscopy of gas and surface species will be presented.