title: Dual wavelength 3.2-μm source for isotope ratio measurements of (13)CH(4)/(12)CH(4).
abstract: Difference frequency generation using one 1.58-μm and two 1.06-μm distributed feedback Bragg-grating laser diodes and a ridge-type PPLN alternately provide two 3.2-μm coaxial waves resonant with individual isotopic transitions separated by 13 cm(-1). The ν(3) band R(6) A(2) allowed transition of (13)CH(4) and the ν(3) band R(6) A(2) weakly allowed transition of (12)CH(4) are an ideal pair for isotope ratio measurements. The (13)CH(4)/(12)CH(4) isotope ratio is determined for three sample gases with a relative uncertainty of 0.7 ‰, and it is confirmed that the temperature dependence is smaller than the uncertainty.
authors.forename: Masashi
authors.initials: M
authors.lastname: Abe
authors.forename: Satomi
authors.initials: S
authors.lastname: Kusanagi
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nishida
authors.forename: Osamu
authors.initials: O
authors.lastname: Tadanaga
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Takenouchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasada