Cantilever enhanced photoacoustic spectroscopy (CEPAS) technology improves the detection ability of weak gas photoacoustic signal effectively utilizing a micro-cantilever acoustic sensor instead of capacitive microphone, which can achieve highly sensitive detection of CO2 and has great significance for environmental monitoring, industrial production control and regional carbon emission monitoring and other applications. A fiber-optic Fabry-Perot (F-P) sensor with a cantilever structure is designed in this work to overcome the disadvantage of the complication of traditional mechanical cantilever photoacoustic spectroscopy system. The photoacoustic spectroscopy system is established based on the resonance enhancement of the fiber cantilever acoustic sensor with a 2.0 μm distributed feedback (DFB) laser, which combines the technologies of wavelength modulation and second-harmonic detection for measuring CO2 concentration. The experimental results show that the concentration calibration curve has a good correlation of 0.9765, and the detection limit of CO2 concentration reaches 0.044×10-6, which verifies the feasibility of the system for detecting atmospheric CO2 concentration.
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