title: Circular paraboloid reflection cell for laser spectroscopic trace gas analysis.
abstract: Absorption cells with circular geometry are a class of multipass reflection cells consisting of a single, circular mirror. They can be particularly favorable for trace gas measurements because of their mechanical robustness, simplicity, and their optical versatility. In this article, we present detailed theoretical considerations and ray tracing simulations for the optimization of the optical design of circular multipass reflection cells. A parabolic mirror shape in a confocal arrangement is found to be most suitable for long optical paths in a small volume. We experimentally demonstrate more than 12 m optical path in a 14.5 cm diameter gas cell and NO2concentration measurements in ambient air with a measurement precision better than 0.1 ppb.
authors.forename: Markus
authors.initials: M
authors.lastname: Mangold
authors.forename: Béla
authors.initials: B
authors.lastname: Tuzson
authors.forename: Morten
authors.initials: M
authors.lastname: Hundt
authors.forename: Jana
authors.initials: J
authors.lastname: Jágerská
authors.forename: Herbert
authors.initials: H
authors.lastname: Looser
authors.forename: Lukas
authors.initials: L
authors.lastname: Emmenegger