THz-TDS测试中时域脉冲的本质段及其截取模型  

Intrinsic Section and Its Interception Model for Temporal Pulse of THz-TDS

作　　者：苏海霞[1] 张朝晖[1] 赵小燕[1] 李智[1] 燕芳[1] 张寒[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》2013年第4期921-925,共5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(FRF-SD-12-016A)资助

摘　　要：利用太赫兹时域谱仪THz-TDS测试样品并计算太赫兹吸收谱的形态和幅度,是太赫兹定性、定量分析的主要途径。在实验中我们发现,谱的形态和幅度不仅与样品吸收特性有关,而且与计算中所选取的太赫兹时域脉冲的长度密切相关。太赫兹波在片状样品前后表面的多次反射波是造成这个问题的主要原因。太赫兹时域脉冲分为直接载有样品信息的本质段、低信噪比的噪声段和信息重叠的回波段。通过分析太赫兹脉冲的产生机理及脉冲幅度与衰减过程的关系,给出一个半理论半经验的本质段长度截取模型,由此确定进一步计算太赫兹吸收谱的最佳长度。谷氨酰胺(Gln)、组氨酸(His)和胱氨酸(Cys)三种氨基酸样品的实验表明,该文截点位置截取方法的计算结果是稳定有效的。Using THz-TDS to detect the THz temporal pulse and calculate the absorption spectrum of the sample is the main access to qualitative and quantitative analysis.The shape and the amplitude of the THz absorption spectra are not only related to the sample,but also closely related to the length of the chosen THz pulse in the calculation,which was discovered in our experiments.It is the main cause of this problem that the flaky sample reflects the THz wave many times,which will give rise to the Fabry-Perot effect.So the sample-probing temporal signal is divided into the intrinsic section with the sample＇s information directly,low SNR noise section,and unwanted Fabry-Perot reflections section with the overlapped information.Based on THz pulse generation mechanism and the relationship between the pulse amplitude and the attenuate process,a model of intercepting the intrinsic section in terahertz time-domain pulse was proposed and was proved reliable and stable by the results from experiments performed with amino acids： glutamine（Gln）,histidine（His）,and cystine（Cys）.

关 键 词：太赫兹时域脉冲 法布里-珀罗效应 脉冲序列长度 本质段 

分 类 号：O433.51[机械工程—光学工程]