ABSTRACT
Mid-infrared Cavity Ringdown Spectroscopy
Marcel Hemerik, Jeroem Remy, Gerrit Kroesen, Technische Universiteit Eindhoven
A Cavity Ringdown Spectroscopy set-up is being improved and will be used to measure the absolute densities of particles in a silane discharge. The design is based on a 0.1 mW continuous wave mid-infrared laser diode. Extensive research on the beam characteristics pointed out some imperfections on our source and mode selecting devices: a non-negligible amount of energy is lost while the beam passes through the mode selector because of the beam’s unusual diameter, ca. 35 mm. Some solutions are currently being considered to improve our beam quality and successfully manage to send the laser light in the plasma vessel. Some experiments have nevertheless been previously undertaken with a CO plasma, proving that our mid-infrared Cavity Ringdown is a non-intrusive diagnostic and showing very promising results.
