【作者】 袁静；

【导师】 刘劲松；

【作者基本信息】 华中科技大学 ， 光学工程， 2012， 硕士

【摘要】 太赫兹波是指频率范围为0.1~10THz的电磁波。最近20多年来，得益于超快激光技术的迅速发展，太赫兹时域光谱技术作为一种新的、快速发展的光谱分析方法在许多领域备受关注。为了得到太赫兹脉冲的时域波形和频域光谱，而编写的太赫兹时域光谱系统运动控制和数据采集软件，运动控制方便，数据采集处理完整、迅速，有很大的实用价值。以下是本论文的主要研究工作。参与搭建了透射式太赫兹时域光谱系统光路，深入分析了编写运动控制和数据采集软件的功能需求。并基于LabVIEW软件主要编写了步进平移台运动控制和锁相放大器数据采集处理等程序，成功实现了光程差的改变和时域幅值数据采集的一一对应，并完成了对时域波形进行实时快速傅里叶变换，以得到频域光谱。为证明程序的正确性，设计了相关的验证实验。首先加入0.3mm厚的聚四氟乙烯样品进行探测，样品时域信号波形相对于参考信号波形有1.12ps的时间延迟，证明了被测信号为太赫兹信号，即证明了时域波形数据采集程序的可行性。然后将所测时域数据导入Oringin软件中进行快速傅里叶变换得到的频谱图，与直接由LabVIEW快速傅里叶变换程序得到的频谱图对比，二者波形一致，证明了所设计的LabVIEW快速傅里叶变换程序是可行的。最后利用LabVIEW软件得到的频谱图来分析太赫兹脉冲的带宽，并设计了双泵浦光产生太赫兹脉冲的实验，太赫兹脉冲的带宽由2.75THz增加到了5.2THz。为了更方便的搭建和调试光路，也为了使光路系统更加的简单紧凑，根据实际需要，设计了相应的机械零部件，如标定光路高度的光标板零件，装夹探测晶体的晶体盒装置，装夹反射镜的45°底座装置等等。更多还原

【Abstract】 THz wave is a kind of electromagnetic wave whose frequency ranges from0.1THz to10THz. In the last20years, thanks to the rapid development of ultrafast laser technology,THz-TDS as a new and rapid developing spectral analysis method is concerned in manyareas. To get the time-domain waveform and the frequency-domain spectrum, I haveprogrammed a set of procedures about motion control and data acquisition in THz-TDS. Asit’s easy to control move and fast to collect and process data completely, this software hasgood practical value. The followings are this thesis’s main research work.As I have participated in building the light path of transmissive terahertz time domainspectroscopy system, so I could deeply analyze the functional requirements of motioncontrol and data acquisition for programming. And I have programmed a set of proceduresmainly about motion control of stepper translation stage and data acquisition and processingof lock-in amplifier by LabVIEW, which have successfully realized the synchronization ofthe change of optical path’s difference and the time domain data’s acquisition, and moreovercompleted the real-time fast fourier transform of the time-domain waveform to obtainspectrum.In order to prove the procedures’ correctness, I design the corresponding experiment.First I put the PTFE sample into THz-TDS to be detected, finding that there is a1.12ps timedelay between sample’s signal time-domain waveform and reference’s, which proves thatthe measured signal is terahertz signal and the procedures of time-domain data acquisition iscorrect. Then I import the measured time-domain data into the Oringin software to be fastfourier transformed, finding that the frequency-domain spectrum FFT by Oringin is as sameas FFT by LabVIEW, which proves that the LabVIEW FFT procedure is feasible. Finally, Ianalyze the bandwidth from the frequency-domain spectrum, and design the dual-pumpexperiment to obtain THz wave whose bandwidth is increased from2.75THz to5.2THz.To make the optical path’s building and debugging more conveniently, and to makeoptical system more simple and compact, I design the appropriate mechanical partsaccording to actual needs, such as the cursor-plate part which is used to calibrate the opticalpath’s height, the crystal-box device which is used to clamp the detected crystal, and the45-base folder device which is used to clamp the mirror and so on.更多还原