基于TDLAS的纳米光纤甲烷传感器

Nanofiber Methane Sensor Based on TDLAS Technology

展示一种基于可调谐半导体激光吸收光谱技术(TDLAS)的微型化纳米光纤甲烷传感器.在比尔-朗伯定律的基础上,选择1.6 μm附近的甲烷吸收线,对分布式反馈半导体激光器(DFB-DL)进行波长调制,使用锁相放大器解调出二次谐波信号,建立一套完整的基于纳米光纤的TDLAS系统.使用该系统测量室温下不同入射功率和不同压强对二次谐波信号的影响,同时获得了该系统的压力展宽系数和压力频移系数,发现直径较小的纳米光纤可以对甲烷产生更强的吸收.所设计的纳米光纤传感器是一个在低功率条件下进行微量气体测量的有力工具,在气体种类分析和定量分析方面有着巨大的应用潜力.

In this paper,we demonstrate a miniaturized nanofiber methane sensor based on tunable diode laser absorption spectroscopy(TDLAS).Based on the BeerLambert law,we chose a methane absorption line near 1.6μm,performed a wavelength modulation on a distributed feedback diode laser(DFBDL),used a lockin amplifier to demodulate the second harmonic signal,and established a complete TDLAS system based on nanofiber.The system is used to examine the influence of different incident powers and pressures on the second harmonic signal at room temperature.We obtain the system’s pressure broadening and frequency shift coefficients through experiments.It is found that nanofibers with a smaller diameter can produce stronger absorption for methane.Moreover,the designed nanofiber sensor is a powerful tool for tracing gas measurements under low power conditions and has considerable application potential in gas species and quantitative analyses.