Schilt, S.Besson, J. P.Thévenaz, Luc2008-09-292008-09-292008-09-29200510.1051/jp4:2005125002https://infoscience.epfl.ch/handle/20.500.14299/29892WOS:000230014700003The importance of molecular relaxation in photoacoustic spectroscopy is discussed. The particular case of methane monitoring in dry oxygen using a 1.65-μm laser-based photoacoustic sensor is reported. The slow vibration-to-translation energy transfer occurring in this gas mixture results in a drastic reduction of the detection sensitivity. A quadratic response of the sensor to the methane concentration is also reported and explained by molecular relaxation effectstext::conference output::conference proceedings::conference paper