Scientific Results

THz QCL-Based Cryogen-Free Spectrometer for in Situ Trace Gas Sensing

Year: 2013

Authors: Consolino L., Bartalini S., Beere H. E., Ritchie D. A., Vitiello M. S., De Natale P.

Autors Affiliation: CNR, Istituto Nazionale di Ottica and LENS (European Laboratory for Non-linear Spectroscopy), Via Carrara 1, Sesto Fiorentino (FI) 50019, Italy; Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, United Kingdom; NEST, CNR, Istituto Nanoscienze and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa 56127, Italy

Abstract: We report on a set of high-sensitivity terahertz spectroscopy experiments making use of QCLs to detect rotational molecular transitions in the far-infrared. We demonstrate that using a compact and transportable cryogen-free setup, based on a quantum cascade laser in a closed-cycle Stirling cryostat, and pyroelectric detectors, a considerable improvement in sensitivity can be obtained by implementing a wavelength modulation spectroscopy technique. Indeed, we show that the sensitivity of methanol vapour detection can be improved by a factor approximate to 4 with respect to standard direct absorption approaches, offering perspectives for high sensitivity detection of a number of chemical compounds across the far-infrared spectral range.

Journal/Review: SENSORS

Volume: 13 (3)      Pages from: 3331  to: 3340

More Information: This work was partly supported by the Italian Ministry of Education, University, and Research (MIUR) through the program \”FIRB-Futuro in Ricerca 2010\” RBFR10LULP \”Fundamental research on terahertz photonic devices\”. We acknowledge Davide Mazzotti for his valuable contribution and discussions.
KeyWords: Direct absorption; High-sensitivity; High-sensitivity detection; Molecular transitions; Pyro-electric detectors; Spectral range; Trace-gas sensing; Wavelength modulation spectroscopy, Chemical compounds; Chemical detection; Molecular spectroscopy; Quantum cascade lasers; Terahertz spectroscopy, Gas detectors
DOI: 10.3390/s130303331

Citations: 35
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