Near-infrared quartz-enhanced photoacoustic spectroscopy system for ppb-level methane detection

Abstract

In this paper we present a quartz-enhanced photoacoustic spectroscopy (QEPAS) of methane near 1651 nm. QEPAS is a high-sensitivity gas sensing method that relies on detecting acoustic waves generated by gas molecules. The sensor setup consists of a bismuth-doped fiber amplifier (BDFA) operating at 1651 nm that is used to enhance the amplitude of the QEPAS signal and increase the detection sensitivity. With the BDFA delivering ∼250 mW of optical power to the sample, the minimum detection limit of ∼11 ppb was achieved for the integration time of 150 s.