Part-per-trillion level detection of SF 6 using a single-mode fiber-coupled quantum cascade laser and a quartz enhanced photoacoustic sensor
Authors: Spagnolo V., Patimisco P., Borri S., Scamarcio G., Bernacki B.E., Kriesel J.
Autors Affiliation: Dipartimento Interateneo di Fisica, University and Politecnico of Bari, CNR-IFN UOS BARI, Via Amendola 173, Bari, Italy; Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, United States; Opto-Knowledge Systems Inc., 19805 Hamilton Ave., Torrance, CA, United States
Abstract: We will report here on the design and realization of optoacoustic sensors based on an external cavity QCL laser source emitting at 10,54 µm, fiber-coupled with a QEPAS spectrophone module. SF 6 has been selected as the target gas. Single mode laser delivery through the prongs of the quartz tuning fork has been realized using a hollow waveguide fiber with internal core size of 300 µm. The achieved sensitivity of the system was 50 part 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.
KeyWords: Gas sensing; Hollow fiber; Hollow waveguides; Level detections; Opto-acoustic sensors; Photoacoustic sensors; Quartz tuning fork; Single-mode lasers, Nanophotonics; Quantum cascade lasers; Quartz; Sensors; Single mode fibers, Fibers