【作者】 胡旻；

【导师】 刘盛纲；

【作者基本信息】 电子科技大学 ， 等离子体物理， 2009， 博士

【摘要】 太赫兹科学技术发展迅速，而太赫兹辐射源的研发是其中的关键技术。本论文主要探索一种能将电子学与光子学相结合从而产生太赫兹辐射的新型太赫兹源器件，并研究分析其中的一些物理现象和物理机制。在探索电子学与光子学相结合产生太赫兹辐射的过程中，本论文主要研究了如下内容并取得如下结果：一．本论文探讨利用电子注掠过金属表面直接激发金属中的表面等离子体波并与之互作用的可能性。相比于传统的电子或光子直接作用于金属表面激发表面等离子体波，这是一个新的尝试。通过理论推导，证明了电子注的等离子体频率只需达到金属中的等离子体波振荡频率的10^-4倍，就可以直接激发金属中的表面等离子体波并与之互作用。二．本论文探讨了电子注与亚波长孔阵列结构中的仿表面等离子体波互作用的情况。通过理论分析以及计算机粒子模拟，证明了电子注可以与亚波长孔阵列结构中的仿表面等离子体波互作用，并指出此种亚波长孔阵列结构与传统慢波结构相比所具有的优势。利用亚波长孔阵列结构中的透射现象，设计了双电子注与亚波长孔阵列结构的互作用模型，粒子模拟结果证明电子注的调制深度大大加深，从而证明此方法可以产生更大功率的太赫兹输出。三．本论文在研究电子注与亚波长孔阵列结构互作用的过程中，发现了双边的衍射辐射现象。利用经典的基于格林函数的积分方程的方法，从理论上推导了电子注激发亚波长孔阵列结构双边衍射辐射的整个物理过程，求得了各个区域场的解析表达式。运用计算机粒子模拟软件，证明了理论推导的正确性。在此基础上，利用解析解分析了双边衍射辐射的各种情况，并从物理机制上给予了解释。本论文利用电子注作为激发源，验证了亚波长孔阵列的透射现象，阐述了电子注作为激发源比其他平面波激发源所具有的优势，并探讨了结构深度对透射的影响。本论文还对亚波长孔阵列的透射现象进行了微波波段的实验研究，由平面波激发的亚波长孔阵列的透射现象的实验结果，从另一个角度验证了理论推导的正确性及可扩展性。四．本论文探讨了另外一种周期孔阵列结构——光子晶体中的辐射现象。运用平面波展开法和等离子体粒子模拟方法讨论了一维和二维光子晶体中的辐射特性。为了更好的研究，专门设计了粒子模拟的边界条件模块，并取得很好的结果。本论文模拟了电子以不同速度进入一维光子晶体所产生的辐射现象；并从理论上分析了二维光子晶体中可能的辐射现象。验证了前人对二维正方形晶格光子晶体中辐射的分析，运用粒子模拟验证了这些现象，并将这一理论分析拓展至六边形晶格结构光子晶体辐射的分析中。更多还原

【Abstract】 Terahertz Science and Technology have been developed rapidly, and the developments of the radiation sources are one of the key researches in this area. In this work, the major study is to explore a new way of merging the electronics and photonics for the new type terahertz sources and devices.The following results have been achieved in this dissertation:1. The possibility of excitation of surface plasmon in conducting metal by electron beam has been discussed. It has been proven that the surface plasmon can be excited and amplified by electron beam just passing above to the surface of metal. This phenomenon may happen if the plasma frequency is just 10^-4 of the plasmon frequency of metal.2. The subwavelength holes array has been proposed to explore the interaction of electron beam and mimicking surface plasmon. After theoretical analysis and computer simulation, it has been proven that electron beam can excite the mimicking surface plasmon in the subwavelength holes array and interact with it to produce the terahertz radiation. The advantages of subwavelength holes array structure for the electron beam-wave interaction have been revealed comparing with the traditional slow wave structures. The enhanced transmission phenomenon of subwavelength holes array is utilized to design the two beams interaction sources. The results of computer simulation demonstrate that the sources driven by two beams can produce much more terahertz radiation.3. A novel electromagnetic diffraction radiation phenomenon is discovered. It explores that the physics of electromagnetic diffraction radiation of a subwavelength holes array excited by a set of evanescent waves generated by a line current of electron beam. Actived by a uniformly moving line current, numerous physical phenomena occur such as the diffraction radiation on both sides of the array as well as the electromagnetic penetration below the cut-off through the holes. As a result the subwavelength holes array becomes a radiation array. Making use of the integral equation with relevant Green’s functions, an analytical theory for such a radiation system is built up. The results of the numerical calculations based on the theory agree well with that obtained from the computer simulation. The relation between the effective surface plasmon wave, electromagnetic penetration of the holes and diffraction radiation has been revealed theoretically. It has been proven that the phenomena involving the electromagnetic penetration/transmission and diffraction radiation in both sides of the array happen simultaneously. A distinct diffraction radiation phenomenon has been discovered and the mechanism has been disclosed. The experimental research has been carried out in the microwave frequency region. Moreover, the integral equations method for the analytical theory of the diffraction radiation and the electromagnetic penetration/transmission of the SHA can also be extended and explored to other interesting phenomena with SHA structure.4. The work also discusses the diffraction radiation in another periodical structure—Photonic Crystal. Theoretical study and computer simulation on the Vavilov-Cherenkov Radiation （VCR） in 1D and 2D photonic crystal are given in the paper. It has been found previously that there are number of interesting and important behaviors for the VCR in a 2D photonic crystal, such as when the electron energy is lower than the threshold the backward VCR may occur, etc. Some new important features of the VCR in photonic crystal, mainly the radiation excited by a train of electron bunches has been observed and the physical mechanism is examined as well.更多还原