基于DL模型与时域耦合波理论的PCA THz调制机理研究  

Research on mechanism of PCA THz modulation based on the DL model and time-domain coupled wave theory

作　　者：熊中刚 邓琥[1] 熊亮[1] 尚丽平[1] XIONG Zhong-gang;DENG Hu;XIONG Liang;SHANG Li-ping(School of Information Engineering,Southwest University of Science and Technology,Mianyang 621010,China;School of Mechanical Engineering,Guilin University of Aerospace Technology,Guilin 541004,China)

机构地区：[1]西南科技大学信息工程学院,四川绵阳621010 [2]桂林航天工业学院机械工程学院,广西桂林541004

出　　处：《激光与红外》2020年第6期743-748,共6页Laser & Infrared

基　　金：国防基础科研计划研究项目(No.JCKY2018404C007);四川省科技厅重点研发项目(No.2019YFG0114)资助。

摘　　要：太赫兹电导天线是太赫兹源或探测器的最常用器件之一。针对太赫兹波与金属微结构之间的相互作用效应以及远场辐射调制机理问题,本文提出了基于DL模型与时域耦合波理论的光电导天线太赫兹波调制机理研究。在工形光电导天线上引入金属微结构,采用DL模型理论求解瞬态电流以及时变电磁场,并经由格林函数处理后实现PCA THz的远场辐射;同时建立了瞬态电流和局域电磁模式之间的耦合模型,利用时域耦合波理分析了微结构光导天线THz波辐射的机理。研究结果表明:本文引入的微结构改变了等效模型的辐射阻抗,局域电磁模式能够存储能量6 ps后通过调整结构间的耦合系数以散射损耗形式释放出来;且存在耦合作用时,组合微结构对应共振频率处的辐射得到极大增强,该结论为后续光导天线结构设计和太赫兹波辐射调制奠定重要基础。Terahertz photoconductive antenna is one of commonly used devices of terahertz source or detector.Aiming at the interaction between terahertz wave and metal microstructures,and the mechanism of far-field radiation modulation,the mechanism of terahertz wave modulation of photoconductive antennas based on DL model and time-domain coupling wave theory is proposed in this work.The metal microstructure is introduced into the H-shaped photoconductive antenna,and the transient current and time-varying electromagnetic fields are solved by the DL model theory,and the far-field radiation of PCA THz was realized with the green′s function.Meanwhile,the coupling model is established between transient current and local electromagnetic model,and then the mechanism of the microstructure PCA THz wave radiation with time domain coupled wave theory is analyzed.The results show that the radiation impedance of the equivalent model is changed with the microstructure introduced,and the energy can be stored for 6 ps with the local electromagnetic mode and released in the form of scattering loss by adjusting the coupling coefficient between structures.In addition,the radiation of the corresponding resonance frequency of the composite microstructure is greatly enhanced with coupling effect,which lays an important foundation for the subsequent structure design of PCA and THz radiation modulation.

关 键 词：太赫兹波调制 光电导天线 DL模型 时域耦合波理论 局域电磁模式 

分 类 号：TN201[电子电信—物理电子学]