THz时域光谱测试中的散射问题  

Discussion of Scattering in THz Time Domain Spectrum Tests

作　　者：燕芳[1,2] 张朝晖[1] 赵小燕[1] 苏海霞[1] 李智[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 [2]内蒙古科技大学信息工程学院,内蒙古包头014010

出　　处：《光谱学与光谱分析》2014年第6期1473-1476,共4页Spectroscopy and Spectral Analysis

基　　金：中央高校基本科研业务费(FRF-SD-12-016A);国家自然科学基金项目(61302007;60977065)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谱是太赫兹应用的一个重要方面。THz-TDS实验系统中的被测样片一般是多种成份的微粒与稀释剂(PE)按一定摩尔浓度混合研磨后压制而成的薄圆片。一般认为,吸收谱中出现的随频率缓慢上升的基线是源于样品颗粒对THz波的散射。该基线对准确获取吸收谱中的特征吸收峰的峰高和峰形信息产生了影响,故为了进一步对吸收谱实现准确的定量分析,应设法移除基线,消除样品颗粒散射对吸收谱的影响,使吸收谱中的特征吸收峰更准确的体现被测物质在太赫兹频段内的吸收特性。对基线产生的原因进行了分析,对近年来出现的散射处理方法进行了综述,为了验证文献中去除散射方法的合理性,选取三种氨基酸进行实验,对比了去除散射影响前后氨基酸的摩尔浓度计算精度,结果表明,去除散射影响后部分氨基酸的摩尔浓度计算精度得到了提高,最后综合实验结果提出了THz吸收谱中去除散射影响需要进一步研究的方向。Using THz-TDS to extract the absorption spectrum of a sample is an important branch of various THz applications. Basically,we believe that the THz radiation scatters from sample particles,leading to an obvious baseline increasing with fre-quencies in its absorption spectrum.The baseline will affect the measurement accuracy due to ambiguous height and pattern of the spectrum.The authors should try to remove the baseline,and eliminate the effects of scattering.In the present paper,we investigated the causes of baselines,reviewed some of scatter mitigating methods and summarized some of research aspects in the future.In order to validate the correctness of these methods,we designed a series of experiments to compare the computational accuracy of molar concentration.The result indicated that the computational accuracy of molar concentration can be improved, which can be the basis of quantitative analysis in further researches.Finally,with comprehensive experimental results,we pres-ented further research directions on THz absorption spectrum that is needed for the removal of scattering effects.

关 键 词：太赫兹时域光谱 颗粒散射 吸收谱 基线 

分 类 号：TG115.33[金属学及工艺—物理冶金]