太赫兹时域光谱测量液体光学常数的不确定度分析  

Analysis of measurement uncertainty in determining liquids' optical constants by terahertz time-domain spectroscopy

作　　者：张放[1] 杨霏[2] ZHANG Fang YANG Fei(Biochemical Engineering Department,Guiyang Vocational and Technical College,Guiyang 550023, China Guizhou Institute of Metrology,Guiyang 550003, China)

机构地区：[1]贵阳职业技术学院生化工程系,贵州贵阳550023 [2]贵州省计量测试院,贵州贵阳550003

出　　处：《中国测试》2017年第5期30-35,共6页China Measurement & Test

基　　金：贵州省科学基金(J20142107);贵阳职业技术学院科研项目(GYZGY2016YB-36)

摘　　要：为建立太赫兹时域光谱测量液体样品光学常数的不确定度分析模型,针对以比色皿为样品池的太赫兹透射式测量系统,推导其测量方程。确认太赫兹幅值测量、样品厚度、比色皿厚度、比色皿倾角及近似传递函数等误差来源,以及这些误差在测量过程中的传递模型,得到表示它们各自不确定度与合成不确定度关系的解析公式。实验测量邻苯二甲酸二辛酯(DEHP)的折射率和吸收系数,并计算它们各自的测量不确定度的量级分别为0.01和1 cm-1,结果表明该不确定度评定模型可以成为评估光学常数测量结果准确性的基础。To build an uncertainty analytical model for measurement of optical constants of liquid sample by terahertz （THz） time domain spectroscopy, the measurement equations are derived by taking THz transmission system with a cuvette as its sample cell into account. The sources contributing to the measurement error, including the errors in T-ray amplitude,sample thickness, cuvette thickness, cuvette tilting, and systematic error in approximated transfer function, are identified. The error propagation through the measurement process is modeled. The analytical formula representing the relation between a source uncertainty and the output uncertainty is derived. An actual experiment is carried out to obtain the refractive index and absorption coefficient of a Di 2-ethyl hexyl phthalate（DEHP） sample. Their uncertainty is calculated with an order of 0.01 and 1 cm- 1,respectively. The results show that the uncertainty model can be the basis for assessing the measurement accuracy of the optical constants.

关 键 词：太赫兹 光谱学 测量不确定度 比色皿 光学常数 误差传递 

分 类 号：O484.41[理学—固体物理]