基于样片厚度精确估计的THz吸收系数谱算法  

Extracting THz Absorption Coefficient Spectrum Based on Accurate Determination of Sample Thickness

作　　者：李智[1] 张朝晖[1] 赵小燕[1] 苏海霞[1] 燕芳[1] 

机构地区：[1]北京科技大学自动化学院仪器科学与技术系,北京100083

出　　处：《光谱学与光谱分析》2012年第4期1043-1046,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(60977065);中央高校基本科研业务费专项资金项目资助

摘　　要：利用太赫兹时域光谱技术(THz-TDS)提取物质在太赫兹波段的吸收系数谱是太赫兹应用的一个重要方面。由于样品的吸收系数与其厚度存在着复杂的非线性关系,而厚度又不便于直接准确测量,往往造成吸收系数谱的失真。根据Duvillaret等用于LiNbO3的厚度估计方法,改进了谷氨酰胺(Gln)与组氨酸(His)在0.3～2.6THz(1THz=1012 Hz)波段的吸收系数谱的测定和计算。为了说明改进后的吸收系数谱的合理性,设计了一系列实验对比了同种氨基酸在不同浓度下吸收系数的线性符合程度。结果表明,改进后计算出的氨基酸吸收系数与浓度之间存在更好的线性关系,符合Lambert-Beer定律的描述,这为进一步的定量分析奠定了基础。Extracting absorption spectrum in THz band is one of the important aspects in THz applications. Sample＇s absorption coefficient has a complex nonlinear relationship with its thickness. However, as it is not convenient to measure the thickness di rectly, absorption spectrum is usually determined incorrectly. Based on the method proposed by Duvillaret which was used to precisely determine the thickness of LiNbO3, the approach to measuring the absorption coefficient spectra of glutamine and histi dine in frequency range from 0. 3 to 2. 6 THz（1 THz： 10lz Hz） was improved in this paper. In order to validate the correctness of this absorption spectrum, we designed a series of experiments to compare the linearity of absorption coefficient belonging to one kind amino acid in different concentrations. The results indicate that as agreed by LambertBeer＇s Law, absorption coeffi cient spectrum of amino acid from the improved algorithm performs better linearity with its concentration than that from the com mon algorithm, which can be the basis of quantitative analysis in further researches.

关 键 词：太赫兹时域光谱 氨基酸 样片厚度 吸收光谱 

分 类 号：O433.51[机械工程—光学工程]