Mode matching of a laser-beam to a compact high finesse bow-tie optical cavity for quartz enhanced photoacoustic gas sensing

摘要

Highlights?We designed and realized a compact and portable high-finesse optical build up bow-tie cavity.?We optically coupled the bow-tie cavity with a quantum cascade laser source operating at 5.26μm.?We reached a cavity finesse of～2000 corresponding to an optical power enhancement factor of～320.?The build-up cavity has been designed for intracavity-Quartz-enhanced photoacoustic (QEPAS) applications.?The realized bow-cavity will allow to reach sensitivity levels two orders of magnitude better than standard QEPAS.AbstractWe report on the optical characterization of a compact bow-tie cavity composed of two flat mirrors and two concave mirrors, all having a reflectance >99.99% in the spectral range between 4.8μm and 5.3μm, mounted in a stainless-steel enclosure. The cavity was designed for th