We demonstrate a fiber-tip photoacoustic spectrometric sensor for trace gas detection. The sensor head is a miniature fiber-tip hollow-cavity with a deflectable polymer diaphragm. Periodic light absorption of gas molecules within the cavity generates an acoustic pressure wave, which causes deflection of the diaphragm. The hollow cavity also is a Fabry–Perot interferometer with which the diaphragm deflection is detected with high sensitivity. Experimental test around the P(9) absorption line of C₂H₂ achieved a minimum detectable gas concentration of 4.3 ppm with an excitation laser power of 8 mW. The miniature sensor head and fiber optic detection system make this type of spectrometers ideally suited for remote and space-limited applications as well as for multipoint detection in a multiplexed fiber optic sensor network.
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机译:我们演示了用于痕量气体检测的光纤尖端光声光谱传感器。传感器头是带有可偏转聚合物膜片的微型光纤尖端空心腔。空腔内气体分子的周期性光吸收会产生声压波,从而引起膜片偏转。空心腔也是Fabry-Perot干涉仪,通过它可以高灵敏度地检测到膜片挠度。在C 2 H 2的P(9)吸收线上进行的实验测试在8 mW的激发激光功率下可检测到的最低气体浓度为4.3 ppm。微型传感器头和光纤检测系统使这种类型的光谱仪非常适合于远程和空间受限的应用以及多路复用光纤传感器网络中的多点检测。
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