title: An efficient and compact difference-frequency-generation spectrometer and its application to (12)CH(3)D/(12)CH(4) isotope ratio measurements.
abstract: We have developed an efficient and compact 3.4 μm difference-frequency-generation spectrometer using a 1.55 μm distributed feedback (DFB) laser diode, a 1.06 μm DFB laser diode, and a ridge-waveguide periodically poled lithium niobate. It is continuously tunable in the 30 cm(-1) span and is applied to (12)CH(3)D/(12)CH(4) isotope ratio measurements. The suitable pair of (12)CH(3)D ν(4) (p)P(7,6) and (12)CH(4) ν(2)+ν(4) R(6) F(1)((1)) lines enabled us to determine their isotope ratio with a precision repeatability of 0.8‰ using a sample and a working standard of pure methane with an effective signal averaging time of 100 ms.
authors.affiliation: Department of Environmental Science and Technology, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology/4259, Nagatsuta-cho, Midori-ku, Yokohama, 226-8502, Japan. ktsuji@depe.titech.ac.jp
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Tsuji
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Teshima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasada
authors.forename: Naohiro
authors.initials: N
authors.lastname: Yoshida
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis*; D008697:Methane / Q000032:analysis*; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D002247:Carbon Isotopes; D008697:Methane