Open AccessComb-calibrated sub-Doppler spectroscopy with an external-cavity quantum cascade laser at 77 μm
Author(s) -
Bidoor Alsaif,
Davide Gatti,
Marco Lamperti,
P. Laporta,
Aamir Farooq,
Marco Marangoni
Publication year - 2019
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.27.023785
Subject(s) - laser linewidth , quantum cascade laser , frequency comb , optics , spectroscopy , laser , cascade , doppler effect , materials science , cavity ring down spectroscopy , physics , chemistry , chromatography , quantum mechanics , astronomy
We study the frequency noise and the referencing to a near-infrared frequency comb of a widely tunable external-cavity quantum-cascade-laser that shows a relatively narrow free-running emission linewidth of 1.7 MHz. The frequency locking of the laser to the comb further narrows its linewidth to 690 kHz and enables sub-Doppler spectroscopy on an N 2 O transition of the ν 1 band near 7.7 μm with sub-MHz resolution and absolute frequency calibration. The combined uncertainty on the measured transition center is estimated to be less than 50 kHz.