Theoretical analysis and experimental optimization of an elliptical acoustic resonator in quartz-enhanced photoacoustic spectroscopy

Compact optical fiber photoacoustic gas sensor with integrated multi-pass cell

“…Reducing the size of the microphone can allow the use of a compact gas cell but at the expense of the PAS sensitivity considering the tradeoff between the acoustic sensitivity and the element size of the microphone. Although PA signals can be amplified by boosting up the pump power to Watts level via an optical amplifier [10] or using an acoustic resonator to accumulate the acoustic energy [11] , the high-power laser source adds the system cost and the additional acoustic resonant structure inevitably increases the sensor size again. In comparison, quartz-enhanced PAS employs a tiny tuning fork to detect the acoustic waves between its two prongs facilitating the miniaturization of the sensor and have shown excellent sensitivity leveraging the strong mechanical resonance of the tuning fork to amplify the PA signals [12] , [13] , [14] , [15] .…”