基于长度可调T形光声腔和掺铒光纤激光器的光声光谱气体浓度测量系统

应用光声光谱原理设计了气体浓度测量系统。针对C2H2气体运用了掺铒光纤激光器作为光源。光声腔为新型长度可调T形一阶纵向共振式光声腔,调制频率为1099 Hz。将成熟的二次谐波检测技术作为信号处理的基本原理,采用三角波调制并得到受调制后光源输出信号曲线。将二次谐波系数与一次谐波系数的比值作为系统输出,并得到影响其因素的曲线关系。对不同浓度的乙炔气体的实验结果表明,该系统的检测灵敏度为9.634×10^-6,信噪比为41.52 dB。

A Trace-gas Concentration System Based on Photoacoustic Spectroscopy with Erbium Doped Fiber Laser and A T-type Length-regulated Photoacoustic Cell

A trace-gas concentration system is designed based on photoacoustic spectroscopy. Erbium-doped fiber laser is used as a light source for acetylene detection. A T-type length-regulated photoacoustic cell is designed as first longitudinal single reflection resonance mode. The modulation frequency is 1099 Hz.Second-harmonic detection technology is used as the basic principle of the signal processing.Triangular wave is used to modulate the light source signal.The ratio between the second harmonic coefficients and the first harmonic coefficients as the system output, and the relationship curve about impact factors has been drawn. Experimental results with different concentrations of acetylene gas show that, the detection sensitivity of the system is 9.634×10^－6,and signal-to-noise ratio is 41.52 dB.