Research On The Experiment Of Terahertz Time-Domain Spectroscopy

Terahertz radiation is the last region of electromagnetic wave spectrum. As its unique properties, the terahertz radiation has significant academic value and broad applications and perspective on physics, chemistry, medicine, radio astronomy, materials, communication, environmentalology and so on. Terahertz science and technology has been one of the most important scientific issues in the 21 century, and there have been more and more researchers studying in this area.First of all, this paper introduced the research review of the terahertz science and technology, and described the characteristics of terahertz radiation and its application. After that, it was described and discussed that the theories and experiments of generating terahertz radiation with photoconductive antenna and optical rectification as well as detecting terahertz radiation with photoconductive sampling and free space electric-optic sampling, and I made a contrast of the two methods of generation and detection of terahertz radiation.Based on the theory research, I set up a transmission terahertz time-domain spectroscopy system, the emitter is either a photoconductive antenna or a nonlinear optical crystal. In this paper, I studied the transmission terahertz time-domain spectroscopy system systematically, and wrote a program based on Lab VIEW in order to accomplish the scanning and data collection of the system. I also designed and fabricated a balanced detector, investigated the circuit design and device parameters for improving the detection accuracy, and suggested the main points to be considered in process of designing and fabricating. In the end, I described the experimental observations, and analyzed these in detail.