An innovative spectroscopic system based on an external cavity quantum cascade laser (EC-QCL) coupled with a mid-infrared (mid-IR) fiber and quartz enhanced photoacoustic spectroscopy (QEPAS) is described. SF6 has been selected as a target gas in demonstration of the system for trace gas sensing. Single mode laser delivery through the prongs of the quartz tuning fork has been obtained employing a hollow waveguide fiber with inner silver–silver iodine (Ag–AgI) coatings and internal core diameter of 300 μm. A detailed design and realization of the QCL fiber coupling and output collimator system allowed almost practically all (99.4 %) of the laser beam to be transmitted through the spectrophone module. The achieved sensitivity of the system is 50 parts per trillion in 1 s, corresponding to a record for QEPAS normalized noise-equivalent absorption of 2.7 × 10−10 W cm−1 Hz−1/2.
Mid-infrared fiber-coupled QCL-QEPAS sensor / Spagnolo, Vincenzo Luigi; Patimisco, P.; Borri, S.; Scamarcio, G.; Bernacki, B. E.; Kriesel, J.. - In: APPLIED PHYSICS. B, LASERS AND OPTICS. - ISSN 0946-2171. - 112:1(2013), pp. 25-33. [10.1007/s00340-013-5388-3]
Mid-infrared fiber-coupled QCL-QEPAS sensor
SPAGNOLO, Vincenzo Luigi;Patimisco P.;
2013-01-01
Abstract
An innovative spectroscopic system based on an external cavity quantum cascade laser (EC-QCL) coupled with a mid-infrared (mid-IR) fiber and quartz enhanced photoacoustic spectroscopy (QEPAS) is described. SF6 has been selected as a target gas in demonstration of the system for trace gas sensing. Single mode laser delivery through the prongs of the quartz tuning fork has been obtained employing a hollow waveguide fiber with inner silver–silver iodine (Ag–AgI) coatings and internal core diameter of 300 μm. A detailed design and realization of the QCL fiber coupling and output collimator system allowed almost practically all (99.4 %) of the laser beam to be transmitted through the spectrophone module. The achieved sensitivity of the system is 50 parts per trillion in 1 s, corresponding to a record for QEPAS normalized noise-equivalent absorption of 2.7 × 10−10 W cm−1 Hz−1/2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
