Open AccessDual wavelength 32-μm source for isotope ratio measurements of ^13CH_4/^12CH_4
Author(s) -
Matazō Abe,
S. Kusanagi,
Y. Nishida,
O. Tadanaga,
Hirokazu Takenouchi,
Hiroyuki Sasada
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.021786
Subject(s) - optics , materials science , wavelength , isotope , laser , grating , ridge , physics , geology , paleontology , quantum mechanics
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.