Mid-infrared fiber-coupled QCL-QEPAS sensor

作者：Spagnolo Vincenzo^*; Patimisco Pietro; Borri Simone; Scamarcio Gaetano; Bernacki Bruce E; Kriesel Jason

来源：Applied Physics B: Lasers and Optics , 2013, 112(1): 25-33.

DOI：10.1007/s00340-013-5388-3

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 mu m. 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 x 10(-10) W cm(-1) Hz(-1/2).

• 出版日期2013-8