FB-DFWM技术的实验研究

Experimental Research on Forward-Box Degenerate Four-Wave Mixing Technology

介绍了燃烧场微量分子探测简并四波混频技术的工作原理,建立了前向简并四波混频(FB-DFWM)实验系统,利用该系统,测量了甲烷-空气火焰中OH分子的DFWM光谱信号和OH分子的浓度分布,研究了激光能量、调协波长及其他实验条件与信号强度的关系,并探索了如何有效抑制杂散光干扰及提高信号强度等问题。FB-DFWM技术测量OH分子浓度分布结果与微量分子测量技术——激光诱导荧光技术的测量结果一致,验证了该技术测量结果的准确性。

The principle of degenerate four-wave mixing （DFWM） technique was introduced and a experimental system for the forward box degenerate four wave-mixing （FB-DFWM） was established. Using this setup, the DFWM spectra and concentration distribution of OH in a methane-air flame were measured. The relationships between the signal intensity and the parameters such as laser intensity and wavelength and other experimental conditions were studied. The methods on how to improve the signal to noise ratio and suppress the scattered light were investigated. The results of concentration distribution of OH measured by FB-DFWM and LIF techniques agree with each other, showing that the technique has good accuracy for measured results.