Open AccessDirect-comb molecular spectroscopy by heterodyne detection with continuous-wave laser for high sensitivity
Author(s) -
Tsunemi Hasegawa,
Hiroyuki Sasada
Publication year - 2017
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.25.00a680
Subject(s) - optics , heterodyne (poetry) , materials science , spectroscopy , laser , frequency comb , molecular spectroscopy , continuous wave , heterodyne detection , tunable diode laser absorption spectroscopy , absorption spectroscopy , fiber laser , fourier transform spectroscopy , comb generator , distributed feedback laser , physics , fourier transform infrared spectroscopy , quantum mechanics , acoustics
We have demonstrated direct-comb molecular spectroscopy in which an individual-comb mode is resolved by heterodyne detection with a continuous-wave (cw) laser. This simple, fast, and sensitive technique was demonstrated for atomic spectroscopy in [ Appl. Phys. Lett.101, 051105 ( 2012)], but is more suitable for molecular spectroscopy. Four rotation-vibration transitions of methane have simultaneously been recorded in a Doppler-limited resolution using a spectrally broadened comb based on an Er-doped fiber laser and a cw 1651-nm distributed-feedback laser diode. Even though the power level of the comb modes and the sample absorption are weaker than those of the previous studies, in this work the cw laser frequency is stabilized to one of the comb modes, and the data are thereby averaged for extended periods of time, resulting an improvement in sensitivity.