Analytical structure of Hermite Gaussian beam in far field

Based on the vectorial structure of electromagnetic beam and the method of stationary phase, the analytical structure of Hermite Gaussian beam in far field is presented. The structural energy flux distributions are also investigated in the far field. The structural pictures of some Hermite Gaussian beams are depicted in the far field. As the structure of Hermite Gaussian beam is dominated by the transverse mode numbers and the initial transverse Gaussian half width, it is more complex than that of Gaussian beam. The ratios of the structural energy fluxes to the whole energy flux are independent of the transverse mode numbers and the initial transverse Gaussian half width. The present research reveals the internal vectorial structure of Hermite Gaussian beam from other viewpoint.\     

Near-field characteristics of highly non-paraxial subwavelength optical fields with hybrid states of polarization

The vectorial structure of an optical field with hybrid states of polarization(So P) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial So P of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions.     

Vectorial structure of helical hollow Gaussian beams in the far field

The analytical vectorial structure of helical hollow Gaussian beam (HHGB) is investigated in the far field based on the vector plane wave spectrum and the method of stationary phase. The energy flux distributions of HHGB in the far-field, which is composed of TE term with the electric field transverse to the propagation axis, and TM term with the magnetic field transverse to the propagation axis, are demonstrated. The physics pictures of HHGB is illustrated from the vectorial structure, which is important to understand the theoretical aspects of both scalar and vector HHGB propagation.     

涡旋洛伦兹-高斯光束的远场矢量结构特征

利用矢量角谱法和稳相法,研究了涡旋洛伦兹-高斯光束的远场矢量结构特征,导出了横电项(TE项)和横磁项(TM项)远场电磁场和相应能流的解析表达式。通过相应的数值计算,分析了拓扑电荷数对涡旋洛伦兹-高斯光束及其矢量结构项远场能流分布的影响。TE项由位于竖直方向的2瓣或3瓣组成,TM项可由TE项旋转90得到。涡旋洛伦兹-高斯光束在拓扑电荷数小时内部中空,外部亮环均匀分布。增大拓扑电荷数,涡旋洛伦兹-高斯光束外部亮环上的能流呈起伏分布,内部变化相对复杂。涡旋洛伦兹-高斯光束及其矢量结构项的光斑尺寸随拓扑电荷数的增大而增大,但会饱和。研究显示,涡旋洛伦兹-高斯光束在实际应用时拓扑电荷数不宜过大。     

Far field structural characteristics of cosh-Gaussian beam

By means of the theorem of the vectorial structure of electromagnetic beams and the method of stationary phase, the analytical vectorial structure of cosh-Gaussian (ChG) beam in the far field is presented. The light intensity distributions of a ChG beam and its vectorial structure are investigated in the far field. In addition, the influence of the parameters associated with the cosh term on the light intensity distributions of the whole beam and its structure are also analyzed. The analytical formulae obtained here are applicable not only to the non-paraxial case, but also to the paraxial case. The physical picture of ChG beam in the far field is well depicted from the vectorial structure.     

傍轴光束在单轴左手介质中传输的矢量性质

研究了沿光轴入射的傍轴光束在单轴左手介质中传输的矢量性质.通过平面角谱的方法得到了横电(TE)波和横磁(TM)波在单轴左手介质中传输的严格解，并得到了傍轴近似下的矢量传输模型.利用这一模型，分析得到垂直于光轴方向不同偏振态的入射光束在单轴左手介质中同时激发横向场和低阶纵向场.如果单轴左手介质的介电常数张量在沿垂直于光轴方向上的元素不相等，同时磁导率张量在沿垂直于光轴方向上的两元素也不相等(即z方向为光轴方向，_x≠_y,μ_x≠μ_y),那么入射光束激发的横向场的分布与入射光束的初始场分布和偏振态有关，而纵向场的分布与入射光束的偏振态无关，只决定于入射光束的初始场分布. 关键词： 傍轴传输 单轴左手介质 矢量效应     

傍轴光束在单轴晶体中传输的矢量性质

研究了垂直光轴入射的傍轴光束在单轴晶体中传输的矢量性质.通过角谱的方法得到了寻常光（o光）和非常光（e光）在晶体中传输的严格解，并得到了傍轴近似下的矢量传输模型.利用这一模型，分析得到了垂直光轴偏振的入射光束在晶体中只激发o光，而平行光轴偏振的入射光束在晶体中同时激发e光和二阶小量的o光. 关键词： 傍轴传输 单轴晶体 矢量效应     

Analytical vectorial structure of Hermite-cosine-Gaussian beam in the far field

Based on the vector angular spectrum representation of electromagnetic beams and the method of stationary phase, the vectorial structure of a Hermite-cosine-Gaussian (HcosG) beam in the far field is derived in analytical form. Energy flux distributions for the TE term, TM term and the whole beam are represented. The vectorial structures of HcosG beams with different Hermite models are depicted. The effects of cosine displacement parameters on the vectorial structure are also demonstrated. The results may provide a flexible approach to manipulate HcosG beams in free space.     

Airy-Gaussian光束的解析矢量结构

采用矢量角谱的方法分析了Airy-Gaussian光束的矢量结构, 运用静态相位法得出了光束远场矢量结构的解析表达式. 根据得到的TE项和TM项的解析表达式, 分别研究了TE项和TM项及整个光束的能流分布. 更好地阐明了Airy-Gaussian光束的物理图像, 从而为操控光束提供潜在的新方法. 关键词： Airy-Gaussian光束 解析矢量结构 矢量角谱法 静态相位法     

Analytical vectorial structure of Laguerre-Gaussian beam in the far field

Based on the vector angular spectrum of the electromagnetic beam and the method of stationary phase, the analytical vectorial structure of the Laguerre-Gaussian beam has been presented in the far field. According to the analytical electromagnetic representations of the TE and TM terms, the energy flux distributions of the TE term, the TM term, and the whole beam are investigated in the far field, respectively. The formulas obtained are applicable not only to the paraxial case, but also to the nonparaxial case. The physical pictures of Laguerre-Gaussian beams are well illustrated from the vectorial structure, which may provide a new approach to manipulate laser beams.     

On the longitudinal polarization of non-paraxial electromagnetic fields

Within the framework of the angular plane-wave spectrum of the electromagnetic field, the general form is given for the freely-propagating beams, exact solution of the Maxwell equations, that closely approach (in an algebraic sense) to a purely-longitudinal vectorial distribution at some transverse plane. In the rotationally symmetric case, such a field is written as the combination of radial and longitudinal components, whose propagation can be analysed independently. Several illustrative examples are also considered.     

拉盖尔-高斯光束的近场矢量结构特征

直接以麦克斯韦方程组的解表征拉盖尔-高斯光束。基于麦克斯韦方程组解的矢量角谱表述和电磁光束的矢量结构理论,利用一些数学技巧导出了拉盖尔-高斯光束的TE项和TM项在近场的解析表达式。利用所导出的公式,在近场描绘了拉盖尔-高斯光束的TE项、TM项及整个光束的光强分布。并对角度依赖分别为余弦和正弦关系的拉盖尔-高斯光束的矢量结构进行了比较,结果显示两者整个光束的光斑完全相似,唯一的区别是子瓣的空间方位不同且两者的内部矢量结构完全不相同。     

Vectorial structural properties of truncated beam generated by Gaussian mirror resonator in the near field

Internal vectorial structure of the beam generated by the Gaussian mirror resonator (GMR) diffracted through a hard-edged aperture are evaluated in the near-field. Based on the vectorial angular spectrum representation of electromagnetic fields and the paraxial approximation, TE and TM terms of intensity distributions of the beam in the near field are derived in analytical forms, respectively. Numerical results reveal that the behaviors of TE and TM terms not only depend on the parameters of mirror resonators but also relate to the truncated parameter of the aperture. It is also shown that the distributions of TE and TM terms would not keep detached from each other because of the unorthogonality of their vectorial structures in the near field.     

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针对核聚变反应堆中受到复杂磁场作用的限制器叶片,用悬臂导电薄板作为其简化结构,从导电介质所满足的电磁学及力学的基本定律和方程出发,建立了描述其力-电-磁耦合作用下几何非线性动态响应问题的理论模型,给出了数值计算的求解过程,定量模拟了面内磁体力和几何非线性对薄板挠度的影响。仿真结果显示,在横向磁场很小时,面内磁体力和大挠度都不考虑时的线性结果是可靠的,但是随着横向磁场的增加,几何非线性的影响越来越大,面内磁体力的作用也越发明显,且考虑几何非线性得到的挠度峰值要比线性情形的小,这表明了在导电结构设计中必须同时考虑面内磁体力和几何非线性效应。     

矢量空心高斯光束横纵向光场传输特性

基于矢量瑞利-索末菲衍射积分,研究了矢量空心高斯光束横向光场和纵向光场在自由空间中的传输特性.研究结果表明,空心高斯光束的横向光场与纵向光场在传输过程中光强分布情况并不相同,横向光场的光强分布具有旋转对称性,并且保持空心特性的距离受光束阶数的影响,而纵向光场不再具有旋转对称性,并且在理想状态下纵向光场可以一直保持空心特...     

A slow wave with the structure of an electromagnetic wave in piezoelectric and magnetostrictive media

The propagation of elastic waves in piezoelectric and magnetostrictive materials is considered theoretically. It is shown that an elastic wave in a piezoelectric can create not only a longitudinal electric field parallel to the wave normal (longitudinal piezoactivity) but also a transverse field of electric induction (transverse piezoactivity). The presence of a transverse induction field leads to the appearance of a magnetic field perpendicular to the direction of the wave normal and to the induction vector; therefore, the transverse-piezoactive wave is accompanied by a transverse wave having the structure of an electromagnetic wave and propagating with the speed of sound. Transverse-magnetostrictive elastic waves in magnetostrictive dielectrics are accompanied by a similar wave.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 32–36, October, 1976.     

平面横电磁波模的初值问题

经典理论所描述的电场和磁场处处同相的平面电磁波模并不存在.Maxwell方程组的解依赖于 电磁场的初始值或边界条件,根据不同的初始条件解得的平面电磁波模是不同的.结果表明 ,平面电磁波是横波,在不同的位置,由变化的电场激发的磁场或由变化的磁场激发的电场 振幅不同,电场与磁场的相位差也不同. 关键词： Maxwell方程组 最优微分方程 初始条件 平面电磁波     

随机电磁涡旋光束的深聚焦特性

基于德拜矢量积分理论,研究了随机电磁涡旋光束经过大数值孔径透镜之后的聚焦特性及透镜的数值孔径、入射光束的偏振度、拓扑荷以及横向相干长度对焦平面附近聚焦光束的光强分布和相干度的影响.结果表明:适当地选择相关参量,可在焦平面上得到椭圆形光斑的光强分布以及平顶光强分布.随机电磁涡旋光束在焦平面上同一点处两个相互垂直分量之间的相干度,不同两点处两个相同分量之间的相干度以及不同两点处两个相互垂直分量之间的相干度研究表明,入射光束的拓扑荷和横向相干长度对聚焦光束的相干性有着十分明显的影响.     

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分析了电磁波以任意角度入射到有限磁场中的激光等离子体通道天线(LPCA)时的电磁散射特性。根据LPCA的工作原理建立了其电磁分析模型,推导出广义柱坐标系下各向异性磁化等离子体中纵向分量所满足的波动方程和纵向场与横向场的关系,得到LPCA和周围媒质中的电磁场,利用边界切向电磁场连续,得出了散射系数方程。通过计算实例,将结果与文献结果比较,吻合较好。该研究结果预期可应用于高功率微波武器系统的研究。