High-Resolution Spectroscopy in the 11.6-15 {\mu}m Range by a Quasi-cw Difference-Frequency-Generation Laser Source

We report an approach for high-resolution spectroscopy using a widely tunable laser emitting in the molecular fingerprint region. The laser is based on difference-frequency generation (DFG) in a nonlinear orientation-patterned GaAs crystal. The signal laser, a CO2 gas laser, is operated in a kHz-pul...

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Bibliographic Details
Published in:arXiv.org 2022-12
Main Authors: Elkhazraji, Ali, Shakfa, Mohammad Khaled, Lamperti, Marco, Hakimov, Khaiyom, Khalil Djebbi, Gotti, Riccardo, Gatti, Davide, Marangoni, Marco, Farooq, Aamir
Format: Article
Language:English
Subjects:
Absorption spectra
Broadband
Chemical fingerprinting
Gas lasers
High resolution
Line spectra
Quantum cascade lasers
Spectroscopy
Tunable lasers
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Summary:We report an approach for high-resolution spectroscopy using a widely tunable laser emitting in the molecular fingerprint region. The laser is based on difference-frequency generation (DFG) in a nonlinear orientation-patterned GaAs crystal. The signal laser, a CO2 gas laser, is operated in a kHz-pulsed mode while the pump laser, an external-cavity quantum cascade laser, is finely mode-hop-free tuned. The idler radiation covers a spectral range of 11.6 - 15 {\mu}m with a laser linewidth of 2.3 MHz. We showcase the versatility and the potential for molecular fingerprinting of the developed DFG laser source by resolving the absorption features of a mixture of several species in the long-wavelength mid-infrared. Furthermore, exploiting the wide tunability and resolution of the spectrometer, we resolve the broadband absorption spectrum of ethylene (C2H4) over 13 - 14.2 {\mu}m and quantify the self-broadening coefficients of some selected spectral lines.
ISSN:2331-8422
DOI:10.48550/arxiv.2212.09089