连续波频域太赫兹光谱系统的研究  

Continuous-Wave Frequency-Domain Terahertz Spectroscopy System

作　　者：焦宇峰 郭素杰 孔德胤 阮存军[1,2] Jiao Yufeng;Guo Sujie;Kong Deyin;Ruan Cunjun(School of Electronic and Information Engineering,Beihang University,Beijing 100191,China;Beijing Key Laboratory for Microwave Sensing and Security Applications,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191 [2]北京航空航天大学微波感知与安防北京市重点实验室,北京100191

出　　处：《中国激光》2022年第19期318-329,共12页Chinese Journal of Lasers

基　　金：国家自然科学基金(61222110,61831001)。

摘　　要：基于相干探测的太赫兹频域光谱仪(THz-FDS)是国际上正在发展的一种高分辨率太赫兹光谱测量与分析系统。本团队搭建了连续波透射式THz-FDS和反射式THz-FDS系统,并利用两种系统对固体、液体和气体样品进行测量,介绍了测量数据的分析处理方法。采用透射式THz-FDS系统对比研究了极值法和希尔伯特变换法提取样品折射率的特性,同时将希尔伯特变换法用于处理系统信号,准确获取了乳糖一水合物的折射率,并获得了极高的频率分辨率;采用透射式THz-FDS系统结合传输矩阵法,消除了测量液体样品过程中的Fabry-Pérot谐振,成功获得了非极性有机液体样品正己烷和环己烷的折射率。在反射式THz-FDS系统的研究方面,通过自参考方法准确获得了甲醇和乙醇在太赫兹频段的介电常数;研究了单减Kramers-Kronig(SSKK)估计相位误差的方法,成功提取了固体掺杂硅样品在太赫兹频段的折射率和吸收系数,测量和计算数据与前人研究结果基本吻合。本研究为频域太赫兹光谱技术的发展与应用奠定了基础。Objective Terahertz spectroscopy,which mainly includes terahertz time-domain spectroscopy(THz-TDS)and terahertz frequency-domain spectroscopy(THz-FDS),is an important research field of terahertz science and technology.THz-TDS based on the excitation and detection of femtosecond ultrashort laser pulses has been widely used in the study of spectroscopic properties of substances owing to its wide range of operating frequency(0.2--6.0 THz)and high signal-tonoise ratio.However,the resolution of THz-TDS is affected by its detection time window.The oscillatory disturbances generated in the system limit its frequency resolution to GHz,and the mechanical scanning speed is slow.In addition,THz-TDS obtains time-domain signals,and the spectrum of the entire frequency band of the substance must be achieved through a Fourier transform;moreover,it cannot arbitrarily select a certain range of frequencies for measurement.These factors have limited the spectral analysis performance and application of THz-TDS to some extent.Continuous-wave THz-FDS based on coherent detection is another developing terahertz spectroscopy technology with the advantages of high frequency resolution,simple structure,and tunability of the output frequency.Therefore,THz-FDS has gradually become a powerful tool for research on high-Q terahertz devices.With respect to system structure,the THz-FDS system can be divided into reflection type(measuring the reflection spectrum)and transmission type(measuring the transmission spectrum)schemes.In this paper,we mainly solve the construction and performance optimization of transmission and reflection THz-FDS systems and systematically study the data processing methods to extract material electromagnetic parameters.Methods There are different data processing methods for both transmission and reflection THz-FDS structures.For different sample states,such as gas,liquid,and solid,we designed appropriate bearing structures and data processing methods.For the transmission THz-FDS,we compared the three methods of fitting,f

关 键 词：光谱学 太赫兹频域光谱 连续波 透射式太赫兹频域光谱系统 反射式太赫兹频域光谱系统 介电常数 折射率 

分 类 号：O433[机械工程—光学工程]