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

Sensors

Luigi Consolino¹  Saverio Bartalini¹  Harvey E. Beere²  David A. Ritchie²  Miriam Serena Vitiello¹ 

[1] CNR, Istituto Nazionale di Ottica and LENS (European Laboratory for Non-linear Spectroscopy), Via Carrara 1, Sesto Fiorentino (FI) 50019, Italy; E-Mails:;Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK; E-Mails:

关键词: terahertz spectroscopy;    quantum cascade lasers;    trace gas sensing;   

DOI  :  10.3390/s130303331

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.