Consolino L, Bartalini S, Beere HE, Ritchie DA, Vitiello MS, De Natale P. THz QCL-based cryogen-free spectrometer for in situ trace gas sensing.
SENSORS 2013;
13:3331-40. [PMID:
23478601 PMCID:
PMC3658749 DOI:
10.3390/s130303331]
[Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/02/2013] [Accepted: 03/08/2013] [Indexed: 11/22/2022]
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 ≈ 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.
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