Application of quantum cascade lasers and infrared-fibres for the monitoring and control of industrial plasma processes

Quantum cascade lasers (QCL) offer attractive options for the application of mid-infrared absorption spectroscopy for industrial process monitoring and control. In particular the in-situ measurement of reactive plasma compounds can give new insight into the reaction kinetics of industrial plasma processes. For these purposes the compact quantum cascade laser measurement and control system (Q-MACS) has been combined with an infrared-fibre to allow a flexible and completely dust-sealed incoupling of the infrared radiation into the reactor chamber of an industrial plasma surface modification system. The system has been completed with a fast and compact detector and a data acquisition system to monitor concentrations of species of interest in the plasma process online. First tests proofed the potential of this approach.