Preliminary Study Of The Key Components In Terahertz Waveguide System

As a newly burgeoning technology, the technology of terahertz wave emissionand detection was restricted until the21st century. In this new century, owing toworldwide researchers engaging in the theoretical research and applied technologydevelopment, breakthroughs in terahertz research has been obtained in many fields.Kinds of terahertz systems, such as THz spectroscopy and THz imaging device, areavailable commercially. However, in the most of terahertz systems used now,terahertz waves are propagated in the free-space or optical systems based on metalreflectors and waveguides, which are usually large in size and severely affected bythe environmental disturbance. Therefore, flexible, low-cost and low-loss terahertzsystems are required.Based on the problems above, exploratory researches about the polymermicrostructure terahertz fiber and polymer terahertz lens are carried out in this thesis.Using these polymer terahertz devices can make terahertz systems more compact andflexible.This thesis is structured as follows:Chapter1mainly introduces the research background and significance ofterahertz technology, as well as the history of the development of terahertztechnology and research. On this basis, the main research contents of this thesis arepointed out.Chapter2introduces the concepts, classifications, the structural characteristicsand transmission characteristics of the polymer microstructure fibers. An overviewof the polymer microstructure fiber production methods and a briefly discussion ofthe developments and applications of polymer microstructure fiber are alsomentioned in this chapter.Chapter3introduces the waveguide theory based on the finite element method,the structural characteristics and physical properties of Topas COC, and preliminarystudy of the transmission characteristics of Topas COC in the terahertz. Then, thefabrication process of the terahertz lens based on Topas COC is also discussed. In the chapter4, on the basis of the afore mentioned theories of finite elementmethod and Topas COC material properties, the creative design of polymermicrostructured fiber based on thin-walled anti-resonant reflecting waveguidestructure is introduced and discussed. Commercial software Comsol is used fortheoretical simulation of transmission characteristics of the proposed fiber in theterahertz regime.In the chapter5, according to the application requirements of terahertztime-domain system, double-convex lens based on Topas COC is designed by opticaldesign software Zemax. Terahertz biconvex lens with focal length100mm used interahertz system is produced by the hot compression molding machine.Chapter6is a conclusion of this thesis. In this chapter, the preliminary resultsand shortcomings of the thesis are pointed out, and further research directions areproposed.