双光栅光谱仪的光路设计及应用研究

Optical Design and Application of Double Grating Spectrometer

为提高光谱仪在光谱分析中样品浓度预测的准确性和精确度,结合闪耀光栅分光原理,对光栅分光光路进行优化,设计出应用双光栅代替原有单光栅进行分光的光路结构,并进行了理论分析和实验验证。对使用波段为200~800nm的光谱仪分光光路进行改进,应用使用波段为200~400nm,400~800nm的两光栅代替原有单光栅分光。根据地表水环境质量标准,实验中配置了煤油、0#柴油、97#汽油的CCl4样品溶液,分别应用光路改进前后的光谱仪对其进行实验扫描,取得样品溶液的激发、发射光谱图,并根据所得三维荧光光谱数据对样品进行定性定量分析。实验结果显示,单光栅光谱仪对样品浓度预测误差为0.014mg/L,双光栅光谱仪对样品浓度预测误差为0.008mg/L,即应用改进后的双光栅光谱仪所分析的实验结果误差比常规仪器误差小一倍,精确度提高了近一倍。这表明应用双光栅进行分光的光路优化设计可直接提高光栅光谱仪在光谱分析中的准确性和精确度。

In order to improve the accuracy and precision of sample concentration prediction of grating spectrometer in the analysis of three dimensional fluorescence spectra,combined with the theory of blaze grating beam splitter,We optimize the grating spectral optical path,design a structure that using double gratings instead of single grating in the experiment,and the theoretical analysis and experimental verification in the end. Improving the grating spectral optical path for the use of 200 ~ 800 nm wavelength,using the two gratings of 200 ~ 400 nm,400 ~ 800 nm wavelength replace the original single grating. According to the surface water environment quality standard,configure the CCl4 solution of kerosene,0# diesel,97# gasoline,use the spectroscopy improved before and after to scan,obtain the excitation and emission spectra of sample solution,and get the sample concentration prediction according to the three dimensional fluorescence spectrum data. The experimental results show that the sample concentration prediction error is 0. 014 mg / L before the optical path improvement,and that error is 0. 008 mg / L after the improvement,which is smaller than the former one times,that shows the accuracy is raised nearly doubled. This indicates that the optical optimization design of using double grating can directly improve the accuracy and precision where spectrometer is used in the spectral analysis.