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太赫兹波传输及传感若干问题的研究
The Study on Some Questions of Transmission and Sensing with Terahertz Wave
【作者】 崔海霞;
【导师】 万春明;
【作者基本信息】 长春理工大学 , 物理电子学, 2011, 博士
【摘要】 太赫兹(THz=1012Hz)波是指频率在0.1THz-10THz(波长在30μm-3mm)之间的电磁波,在电磁波谱上位于微波和红外线之间。太赫兹以其光子能量很低、穿透能力强、可得到高分辨率的清晰图像等独特的性质以及在探测、成像、传输、频谱等方面巨大的应用价值,吸引了越来越多的科研人员。与此同时,THz传输及传感的研究受到人们的重视,越来越多的科学家投入到太赫兹传输及传感的领域中,目前国内在太赫兹传输及传感方面的研究还处于初级阶段,存在许多亟待解决的问题。因此,本文初步探索THz波传输及传感的若干问题,主要内容如下:1、从广义范畴考虑,提出THz波传输可以分为被动传输型和主动传输型,被动传输型指大气传输;主动传输型指在THz波传输的同时实现THz波的某种功能,包括波导传输和功能传输。2、从THz波大气传输的应用需求出发,对THz波大气传输方程、THz波大气传输模型、THz波大气传输效应分析等内容进行了详细的分析,并给出基于太赫兹时域光谱(Terahertz Time-Domain Spectroscopy,THz-TDS)大气传输的方案设计。3、对THz波反射镜、偏振器、透镜、衰减器、滤波器、金属网栅进行分析讨论;对THz波传输损耗进行了理论分析及实验研究,实验结果表明,金属镀银层的空心THz波导具有低损耗、柔韧性好的优点,适合长距离传输,传感和通信。4、利用有限元方法对THz波光子晶体光纤进行了理论设计,对实芯折射率引导型高密度聚乙烯光子晶体光纤的THz波传输及THz波倏逝波传感情况进行了分析,并对吸收、损耗等方面的特性进行了讨论。重点模拟分析了光子晶体光纤孔芯的变化对THz传输及THz倏逝波传感的影响。5、提出基于局域增强、高灵敏度、均匀多孔光子晶体光纤THz波倏逝波传感的方法。
【Abstract】 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.
【Key words】 Terahertz (THz) wave; Transmission; High Density Polyethylene(HDPE); Photonic Crystals Fiber ( PCF); Fiber sensing;