Saturated absorption in a rotational molecular transition at 2.5 THz using a quantum cascade laser

Journal Article · Mon Jan 12 00:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4905872· OSTI ID:22399079

Campa, A.; Ravaro, M.; Mazzotti, D.; Bartalini, S.; De Natale, P. ^[1]; Vitiello, M. S. ^[2]

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1. INO, Istituto Nazionale di Ottica-CNR, Largo E. Fermi 6, Firenze I-50125 (Italy)
2. NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa I-56127 (Italy)

We report on the evidence of saturation effects in a rotational transition of CH{sub 3}OH around 2.5 THz, induced by a free-running continuous-wave quantum cascade laser (QCL). The QCL emission is used for direct-absorption spectroscopy experiments, allowing to study the dependence of the absorption coefficient on gas pressure and laser intensity. A saturation intensity of 25 μW/mm{sup 2}, for a gas pressure of 17 μbar, is measured. This result represents the initial step towards the implementation of a QCL-based high-resolution sub-Doppler THz spectroscopy, which is expected to improve by orders of magnitude the precision of THz spectrometers.

• OSTI ID: 22399079
• Journal Information: Applied Physics Letters, Vol. 106, Issue 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
ABSORPTION SPECTROSCOPY
ACCURACY
DOPPLER EFFECT
EMISSION
IMPLEMENTATION
LASERS
METHANOL
RESOLUTION
SATURATION