A compact portable photoacoustic spectroscopy sensor for multiple trace gas detection

A compact, highly sensitive, and cost-effective photoacoustic spectroscopic sensor for multiple trace gas detection was reported with a self-designed compact distributed feedback laser array and a 2-channel dual phase field programmable gate array based digital lock-in amplifier, only twentieth in size and weight of the commercial instruments. The capability of the portable sensor was verified by measuring CH₄ and C₂H₂ simultaneously. With an integrated nonlocal means algorithm denoising, noise-equivalent concentrations were achieved as 6.89 ppb for CH₄ and 2.74 ppb for C₂H₂, respectively, corresponding to a normalized noise equivalent absorption coefficient of 1.1 × 10⁻¹⁰ cm⁻¹ W/Hz^−1/2, a 79 folds higher than the original data. The results demonstrate that the developed minimized sensor has the potential for sensitive and portable measurement of multiple trace gases.