不均匀磁化薄膜中静磁波对导波光的Bragg衍射

研究了横向不均匀偏置磁场作用下掺Bi的YIG薄膜中微波静磁波的激发和传播特性;采用变分方法计算了静磁正向体波的色散关系和交变磁化强度,分析了不均匀场对静磁波－导波光耦合的影响理论计算得到的衍射效率曲线与实验结果基本一致,表明适当不均匀场可以大大提高磁光Bragg器件的衍射性能.     

斜向静磁场中光导波模式转换与衍射理论

应用经典场论和耦合模理论计算了斜向静磁场作用下,磁性薄膜波导中静磁波与导波光的相互作用.计算结果表明,与垂直静磁场情形相比,斜向静磁场时的相匹配条件有所变化,由于磁性薄膜波导中法拉第磁光效应增强等因素,导波光的Bragg衍射效率得以显著增加.这有利于应用YIG等低损耗磁性薄膜做成高衍射效率的磁光波导器件,亦有利于降低Bi∶YIG等高比法拉第旋转的磁光薄膜波导器件的体积和损耗.此外,理论指出的在斜向静磁场条件下所具有的一些磁光特性与实验结果亦符合得很好.关键词：     

静磁波与导波光的磁光耦合理论

根据耦合模理论,分析了砂光波导中静磁波与导波光的相互作用特点。给出了导波光模式之间的耦合方程。理论分析表明,仅当垂直磁化时,发生模式转换的导波光材被全部衍射,此时衍射效率等于模式转换效率。计算了斜向场作用下ＹＩＧ薄膜中导波光的反斯托克斯相互作用衍射效率,所得结论与实验结果一致。适当倾斜静磁场,导波光的模式转换和衍射效率均可比垂直磁化时间显提高。同时改变静磁体波传播方向和斜向场的偏离方向（与垂直方向     

斜向静磁场中的薄膜磁光效应和静磁波传播特性

理论计算表明,与垂直静磁场情形相比,斜向静磁场可以明显增强磁性薄膜波导中的法拉第效应,同时会引起静磁波共振频率和带宽等许多静磁波特性的变化.合理利用这些变化特性,可望大幅度提高导波光的衍射效率,改善磁光波导器件的特性.关键词：     

多频微波静磁波与导波光互作用研究

分析了磁光薄膜中同时激发的多个频率的静磁波对导波光的衍射作用过程,以三频为例推导了三级近似的耦合模方程,对于两频磁光作用的理论计算与实验基本一致.对于三频磁光作用,数值分析结果表明：对于主衍射效率（PrincipleDiffractionEfficiency,PDE）,小信号时只需考虑一级磁光作用.在超出小信号范围且PDE达到峰值之前,第三级磁光作用对PDE影响很小,只需考虑前两级磁光作用.小信号时,得到了PDE的近似解析表达式,在一定的频率间隔范围内与耦合方程的一级近似解较为符合.     

磁光Bragg衍射中的相位失配分析

给出了任意倾斜偏置磁场作用下相位失配时微波静磁波与导波光的磁光耦合方程,分析了相位失配对导波光衍射效率及其衍射方向的影响.计算了YIG薄膜波导中静磁反向体波与导波光非共线作用的Bragg衍射效率, 传统磁化时计算结果与实验结果一致.计算表明,与传统磁化情形相比,适当的偏斜磁场可使导波光衍射效率提高6dB以上;当导波光入射角保持不变时,由磁场方向改变引起的相位失配对衍射效率的影响不大.因此,优化偏置磁场方向是改善磁光Bragg器件衍射性能、提高磁光带宽的有效方法.关键词：磁光效应Bragg衍射静磁波     

利用均匀静磁场偏转带电粒子

本文叙述了在真空靶室中探测中性射线时在混合辐射条件下，为有效地偏转各种带电粒了，以消除其本底，提高测试的可信度，采用了均匀静磁偏转手段，效果很好。     

静磁波器件的现状和发展

在磁偏置YIG薄膜中可以传播一种与电子自旋紧密相关的静磁波(MSW)。它具有可直接工作于常用微波波段、可以电调谐、频带宽等优点,可以满足通信、电子对抗等信号处理系统提出的新要求。本文综述了这种新器件的工作原理、主要形式、系统应用、发展历史、现状及前景展望。     

非均匀磁场中的剪切阿尔芬波涡旋

本文研究了非均匀磁场中非线性剪世阿尔芬波，研究表明，在非均匀磁场情况下，阿尔芬波通过自相互作用也可以形成避域涡旋结构。磁场的非均匀性将导致传播区的展宽。     

高强度均匀静磁场中氢原子能级的计算

采用一种简便的变分法,计算了在均匀高强度静磁场下氢原子的１１个低能态能级和平均半径,讨论了高强度磁场对能级和半径的影响。     

Mode Conversion and Diffraction of Guided Optical Waves from Magnetostatic Waves under Inclined Bias Magnetic Field

The noncollinear interaction of guided optical waves with magnetostatic waves under inclined bias magnetic field is theoretically studied in detail. Similar approach can also be applied to the collinear interaction. Calculation results indicate that the diffraction efficiency (DE) in magnitude is equal to the mode-conversion efficiency (MCE) under vertical bias magnetic field, but they differ greatly under inclined bias magnetic field. By comparison to the case of vertical magnetization, the DE or the MCE can be greatly increased under inclined magnetic field. The characteristic of the DE curves obtained is basically in agreement with the experimental result.``     

Mode Conversion and Diffraction of Guided Optical Waves from Magnetostatic Waves under Inclined Bias Magnetic Field

The noncollinear interaction of guided optical waves with magnetostatic waves under inclined bias magnetic field is theoretically studied in detail. Similar approach can also be applied to the collinear interaction. Calculation results indicate that the diffraction efficiency (DE) in magnitude is equal to the mode-conversion efficiency (MCE) under vertical bias magnetic field, but they differ greatly under inclined bias magnetic field. By comparison to the case of vertical magnetization, the DE or the MCE can be greatly increased under inclined magnetic field. The characteristic of the DE curves obtained is basically in agreement with the experimental result.     

Tesla变压器耦合系数的静磁场解法

 为研究Tesla变压器耦合系数与各参量的关系,采用静磁场分析方法,从柱坐标系磁场Laplace方程出发,推导出磁场级数表达式的系数矩阵方程组,计算出磁芯磁场的轴向分布和间隙磁场的轴向、径向分布。引入了一种平均耦合系数概念——次级绕组每匝线圈具有独立的耦合系数,用全部单匝耦合系数的平均值作为Tesla变压器的耦合系数。重点研究了平均耦合系数与磁芯纵横比、半径比、初级绕组-磁芯长度比、磁芯材料磁导率的相对变化关系。结果表明:增大纵横比、减小半径比是提高Tesla变压器耦合系数的有效方法;增大磁芯材料的磁导率可提高耦合系数,但效果随磁导率增大而降低;初级绕组长度与磁芯长度之比约为0.7时,耦合系数达到最大值。     

Double-resonant extremely asymmetrical scattering of electromagnetic waves in non-uniform periodic arrays

A new type of Bragg scattering – double-resonant extremely asymmetrical scattering (DEAS) of optical waves in oblique, non-uniform, periodic Bragg arrays is analysed theoretically and numerically. Steady-state DEAS is demonstrated to occur in the extremely asymmetrical geometry where the scattered wave propagates parallel to the front array boundary. The non-uniform array is represented by two joint uniform, strip-like, periodic arrays with different phases (and amplitudes) of the grating. DEAS is characterised by a unique combination of two simultaneous resonances with respect to frequency and phase variation at the interface between the joint arrays. As a result, a strong resonant increase in the scattered wave amplitude compared with the amplitude of the incident wave is predicted and investigated theoretically. The amplitude of the incident wave inside the array is also shown to increase resonantly in the middle of the array where the step-like variation in the phase of the grating takes place. The effect of different widths of the joint arrays, and magnitudes of the grating amplitudes on DEAS is analysed. Physical explanations of this type of scattering, based on the diffractional divergence of the scattered wave from one of the joint arrays into another, are presented.     

Tesla变压器耦合系数的静磁场解法

为研究Tesla变压器耦合系数与各参量的关系,采用静磁场分析方法,从柱坐标系磁场Laplace方程出发,推导出磁场级数表达式的系数矩阵方程组,计算出磁芯磁场的轴向分布和间隙磁场的轴向、径向分布。引入了一种平均耦合系数概念——次级绕组每匝线圈具有独立的耦合系数,用全部单匝耦合系数的平均值作为Tesla变压器的耦合系数。重点研究了平均耦合系数与磁芯纵横比、半径比、初级绕组-磁芯长度比、磁芯材料磁导率的相对变化关系。结果表明:增大纵横比、减小半径比是提高Tesla变压器耦合系数的有效方法;增大磁芯材料的磁导率可提高耦合系数,但效果随磁导率增大而降低;初级绕组长度与磁芯长度之比约为0.7时,耦合系数达到最大值。     

Thermal Entanglement of a Three-Qubit Heisenberg Chain with a Nonuniform Magnetic Field

The thermal entanglement of a three-qubit Heisenberg chain under a nonuniform magnetic field is studied. It is very interesting to note that the next nearest neighbor entanglement （NNNE） could be larger than the nearest neighbor entanglement （NNE）. We analyze the ground state entanglement, and give the conditions that NNNE is larger than NNE near zero temperature. Our results also show that the nonuniform field could induce the entanglement and improve the threshold temperature at certain parameter region.