Intra-cavity photoacoustic spectroscopy dual-gas detection system utilizing dual wavelength fiber laser

Abstract

An intra-cavity photoacoustic spectroscopy dual-gas detection system using dual wavelength fiber laser has been developed and experimentally demonstrated. The output wavelength of the fiber laser can be tuned within the spectral range of 1520–1600 nm. Using a single fiber laser, the detection of different gases can be easily achieved by changing the wide fiber Bragg grating (FBG) and seed laser. Photoacoustic spectroscopy with the laser intra-cavity technique is employed to achieve high detection sensitivity. The mixture of carbon dioxide (CO2) and acetylene (C2H2) is selected as target gas for evaluating the detection characteristics of the dual-gas detection system. The minimum detection limits (MDLs) of ∼71.82 ppm for monitoring CO2 and ∼924.24 ppb for monitoring C2H2 are realized. The concentrations of CO2 and C2H2 are linearly fitted with the photoacoustic signal, with R-squared values of 0.99859 and 0.99732, respectively, proving the accuracy and robustness of the dual-gas detection system.