The Study On Some Questions Of Transmission And Sensing With Terahertz Wave

Terahertz (THz) waves are electromagnetic waves in the frequency range from 0.1 to 10THz (3 to 0.03 mm).They cover the so-called "unexplored" range between visible light and radio wave, so named due to the difficulty of generating and detecting waves in this region. THz radiation exhibits great potential applications, for example, exploration, imaging, transmission and spectrum analysis et al, with the characters of penetration ability, low photon energy, high resolved imaging. Meanwhile, the transmission and sensing of terahertz waves now rank the most critical issues in the terahertz technology. However, terahertz wave transmission and sensing in the our nation's researches are at the beginning now and there are many problems to be solved.In this paper, we put our attentions to THz wave transmission and sensing, the main contents are summarized as follows:1,THz transmission can be divided into passive transmission and active transmission, passive transmission refers to propagation, atmosphere propagation is a typical transmission, active transmission means not only transmission but also completing some functions, it includes waveguide transmission and functional transmission.2,Knowledge of the transmission of terahertz wave is very important for terahertz technology and its applications. We analysis detailed the atmospheric propagation model of terahertz wave, propagation effects, propagation equation, then carry out atmospheric propagation measurement system based on Terahertz time-domain spectroscopy(THz-TDS).3,Based on the functional transmission definition, THz wave reflector, polarization, lens, attenuators, filter and metal grids are analyzed theoretically and studied. We conduct terahertz transmission loss characters from theory and experiment. Experiment results show that hollow-core terahertz waveguide with silver layer have low loss, good flexible characteristics, experiment results are conformed with theory simulation, this kind of terahertz waveguide is suitable for long distance transmission, sensing and communication.4,Using the finite element method to simulate THz wave transmission and sensing characteristics with Photonics Crystal Fiber(PCF). According to solid PCF characteristics, the refractive index, attenuation and loss are discussed. And we put emphasis on evanescent wave sensing influence of by changing hole-shape of PCF in THz wave region. Then we simulate and calculate THz-(High Density Polyethylene) HDPE-PCF some parameters, at last the design considerations are given.5,A kind of porous fiber used for sensing based on THz evanescent wave are designed and investigat(?) This kind of fiber can offer the enhancement of the guide mode field and high sensitivity.