基于吸收光谱的光程长度测量方法研究

Study on Light Length Measurement of Absorption Spectroscopy

基于吸收光谱的基本原理,通过计算比尔-朗伯定律数学表达式中的参数实现了光程长度的测量。分析了高斯线型、洛伦兹线型和Voigt线型,采用了Voigt线型对光谱信号进行拟合。研究了Voigt线型峰值计算方法、洛伦兹线宽计算和误差函数求解三个内容。利用可调谐半导体激光吸收谱技术(TDLAS)中的直接吸收谱技术测量了氧气的吸收光谱,得到拟合的光谱峰值数据。将峰值数据带入比尔-朗伯定律数学表达式中,计算出实验光程长度为66.55cm。对比测量值66.04cm,测量精度为0.78%,该方法用于光程长度测量是可行的。

Based on absorption principle,the paper calculated parameters of Beer-Lambert law to measure the light length.The paper analyzed Gaussian lineshape,Lorentzian lineshape and Voigt lineshape, and used the Voigt lineshape to fit the spectrum signal.The peak value of the Voigt lineshape,Lorentzian width and error function were also studied.The direct absorption spectroscopy of TDLAS was used to measure the oxygen absorption spectrum getting the fitted peak value.The light length was calculated as 66.55 cm through putting the peak value into the Beer-Lambert function.The value of comparative measurement was 66.04 cm, and the measurement accuracy was 0.78%.So,this method is suitable in light length measurement.