title: Parts per trillion sensitivity for ethane in air with an optical parametric oscillator cavity leak-out spectrometer.
abstract: Spectroscopic detection of ethane in the 3-microm wavelength region was performed by means of a cw optical parametric oscillator and cavity leak-out. We achieved a minimum detectable absorption coefficient of 1.6 x 10(-10) cm 1/square root of Hz, corresponding to an ethane detection limit of 6 parts per trillion/square root of Hz. For 3-min integration time the detection limit was 0.5 parts per trillion. The levels are to our knowledge the best demonstrated so far. These frequency-tuning capabilities facilitated multigas analysis with simultaneous monitoring of ethane, methane, and water vapor in human breath.
authors.affiliation: Institut für Lasermedizin, Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
authors.forename: Golo
authors.initials: G
authors.lastname: von Basum
authors.forename: Daniel
authors.initials: D
authors.lastname: Halmer
authors.forename: Peter
authors.initials: P
authors.lastname: Hering
authors.forename: Manfred
authors.initials: M
authors.lastname: Mürtz
authors.forename: Stephan
authors.initials: S
authors.lastname: Schiller
authors.forename: Frank
authors.initials: F
authors.lastname: Müller
authors.forename: Alexander
authors.initials: A
authors.lastname: Popp
authors.forename: Frank
authors.initials: F
authors.lastname: Kühnemann