Amplitude Modulated Quantum Cascade Laser Based SF_6 Gas Sensing

摘要

A portable SF_6 detector based on quartz enhanced photoacoustic spectroscopy technique and amplitude modulated Quantum Cascade laser (QCL) has been developed. The detector uses a miniature quartz tuning fork and lock in amplifier to minimize noise. The sensor was used to measure SF_6 gas concentration in air and the minimum detection limit (at 3σ) of the detector was found to be ～120 ppb with a lock-in time constant of 1 s.