Acoustic Detection Module Design of a Quartz-Enhanced Photoacoustic Sensor

Abstract

This review aims to discuss the latest advancements of an acoustic detection module (ADM) based on quartz-enhanced photoacoustic spectroscopy (QEPAS). Starting from guidelines for the design of an ADM, the ADM design philosophy is described. This is followed by a review of the earliest standard quartz tuning fork (QTF)-based ADM for laboratory applications. Subsequently, the design of industrial fiber-coupled and free-space ADMs based on a standard QTF for near-infrared and mid-infrared laser sources respectively are described. Furthermore, an overview of the latest development of a QEPAS ADM employing a custom QTF is reported. Numerous application examples of four QEPAS ADMs are described in order to demonstrate their reliability and robustness.

Long-distance in-situ methane detection using near-infrared light-induced thermo-elastic spectroscopy

“…The resonant frequency and the Q-factor of the QTF are two important parameters for a QTF-based sensor system [ 23 ]. The Q-factor of the QTF was calculated by measuring the bandwidth △ f over which the amplitude is 1/√2 of the resonant amplitude [ 24 ].…”

Roadmap on nonlinear optics–focus on Chinese research

“…In QEPAS, a quartz tuning fork (QTF), as depicted in figure 26(a), is employed as a resonant acoustic transducer, replacing the conventional broadband microphone. Consequently, QEPAS unites the main characteristics of PAS with the advantages of using a QTF, providing an ultra-compact, cost-effective, robust acoustic detection module [172].…”

A NDIR Mid-Infrared Methane Sensor with a Compact Pentahedron Gas-Cell

“…Therefore, CH 4 detection is crucial in both industrial and in environmental scopes [ 3 ]. Numerous techniques have been successfully used in CH 4 detection, such as tunable diode laser absorption spectroscopy (TDLAS) [ 6 , 7 , 8 ], quartz-enhanced photoacoustic spectroscopy (QEPAS) [ 9 , 10 , 11 ], and cavity enhanced absorption spectroscopy (CEAS) [ 12 , 13 , 14 ]. These kinds of CH 4 sensors target very low detection limits (DL) at parts-per-billion (ppb) or even parts-per-trillion (ppt) levels.…”