Yang Tianhe, Chen Weigen, Zhang Zhixian, Lei Jiali, Wan Fu, Song Ruimin
Opt Express. 2021 Jan 18;29(2):2142-2152. doi: 10.1364/OE.415607.
A multiple reflections-enhanced fiber-optic photoacoustic (PA) gas sensor for gas micro-leakage is introduced. Multiple reflections of the excitation laser occur on the inner surface of a reflective ring to enhance the PA signal. The PA signal is obtained by measuring the deflection of the gold-coated poly (phenylene sulfide) (PPS) diaphragm with a Fabry-Perot interferometer (FPI). The second harmonic wavelength modulation spectrum (2f-WMS) technology can essentially eliminate the fundamental frequency noise generated by the wavelength-independent absorption of the reflective ring. Experimental results show that the PA signal can be effectively enhanced 11.7 times by the multiple reflections optical path compare with the double-pass optical path. The minimum detection limit of the system is achieved to be 23.6 ppb. The designed PA gas sensor is suited for remote detection of gas micro-leakage.
介绍了一种用于气体微泄漏检测的多重反射增强型光纤光声（PA）气体传感器。激发激光在反射环的内表面发生多次反射以增强光声信号。通过使用法布里-珀罗干涉仪（FPI）测量镀金聚苯硫醚（PPS）膜片的偏转来获取光声信号。二次谐波波长调制光谱（2f-WMS）技术可以基本消除由反射环的与波长无关的吸收产生的基频噪声。实验结果表明，与双程光路相比，多重反射光路可使光声信号有效增强11.7倍。该系统的最低检测限达到23.6 ppb。所设计的光声气体传感器适用于气体微泄漏的远程检测。
