Research On The Construction And Application Of Terahertz Time-domain Spectroscopy Imaging System

The research of terahertz time domain spectroscopy began in 1990 s,which is the key technology of the application of terahertz wave,and has great value in research and application.THz imaging methods are usually used in the fields of continuous wave imaging,scanning imaging,CCD real-time imaging and near field imaging.The study of THz time-domain spectroscopy imaging system as the main research direction,first from the performance parameters of several common imaging modalities compared and choose the relatively good performance of scanning imaging were used to construct the system.Then,according to the functional requirements of terahertz time-domain spectroscopy system,the Lab VIEW software program is written.Finally,the use of the scanning imaging system for hidden objects and energetic materials is studied.Specific research work includes:(1)To establish a terahertz time-domain spectral imaging system,according to the working principle and components performance,and in accordance with the optical platform to build a method to design and build the optical path.Terahertz time-domain spectral imaging system mainly consists of Ti: sapphire lock mode-locked femtosecond laser,time delay to the translation table,two axis translation Taiwan,terahertz radiation generation device,terahertz detection device and a lock-in amplifier and other equipment device.Debugging and analyzing the system to achieve the highest performance.(2)According to functional requirements of the terahertz time-domain spectrum scanning imaging system,Lab VIEW software modular program written,including parameter settings,motion control,waveform and image display,data acquisition,data storage,data processing and off-line data transfer and so on function module.Understanding of the required virtual instrument performance and command,to master the relevant theoretical knowledge,mainly related to the detection principle,fast Fu Liye transform theory,time domain spectroscopy data processing theory and phase correction algorithm.The data are processed from two aspects of time domain and frequency domain,and the two aspects of waveform andimage display are obtained respectively.(3)Using terahertz time-domain spectroscopy scanning imaging system imaging of concealed objects,analysis of the results of the imaging system,from the noise processing,resolution enhancement,edge detection,image processing to the imaging result using MATLAB software,then the analysis system of the resolution.Then,the data in time domain and frequency domain are obtained,and the waveform and the image of energetic materials are obtained,so that the four kinds of energetic materials can be distinguished.