厄米-余弦-高斯光束通过具有光阑光学系统时的传输特性

当厄米_余弦_高斯光束通过带有矩形光阑的一阶ABCD近轴光学系统时,可由Collins公式给出其场分布的积分形式。将其中硬边光阑的窗口函数写成矩形函数,并将矩形函数用高斯函数展开,通过积分可得到由光阑限制的厄米_余弦_高斯光束传输的解析式。分析和讨论了厄米_余弦_高斯光束通过具有圆孔光阑限制的薄透镜系统时的情况,其结果与直接用广义衍射积分公式进行复杂数值计算时的结果完全一致。这样不仅便于进行物理分析,而且也节省了计算机的计算时间。     

高斯光束第Ⅱ类二次谐波振荡的离散效应

利用直观推断法(heuristc)讨论了离散效应在高斯光束第Ⅱ类相位匹配(PM)二次谐波振荡(SHG)过程中的影响,导出了适用于任意离散参量B和聚焦参量ξ的高斯光束第Ⅱ类PMSHG转换效率的孔径积分公式.     

非高斯噪声对非线性系统的影响

文章采用了路径积分近似、泛函近似两种近似理论推导出了含非高斯噪声并且噪声之间存在耦合的光学双稳系统的定态分布以及平均首通时间的表达式。分析了偏离高斯噪声参量，噪声间的耦合强度对噪声诱导的类相变的影响。结果表明：改变噪声间的耦合强度能诱导重复类相变，改变偏离高斯噪声参量能诱导一级类相变。分析了偏离高斯噪声参量，噪声间的耦合强度对平均首通时间的影响。结果表明：改变噪声间的耦合强度，偏离高斯噪声参量皆能使平均首通时间曲线从单调递减变为单峰。采用了数值模拟分析定态分布以及平均首通时间，数值模拟的结果与理论分析结果相一致，从而验证了理论近似的可行性。     

高斯光束第Ⅱ类二次谐波振荡的离散效应

利用直观推断法(heuristc)讨论了离散效应在高斯光束第Ⅱ类相位匹配(PM)二次谐波振荡(SHG)过程中的影响,导出了适用于任意离散参量 B和聚焦参量ξ的高斯光束第Ⅱ类PM SHG转换效率的孔径积分公式.     

非傍轴贝塞尔-高斯光束在自由空间的传输

从瑞利-索末菲衍射积分出发,推导出任意阶非傍轴贝塞尔-高斯光束在自由空间传输的解析表达式.非傍轴贝塞尔光束和非傍轴高斯光束等的传输方程都可以作为本文一般结果的特例而得出.物理分析和数值计算表明,当高斯和贝塞尔部分的横向尺度与波长相比拟或小于波长时,应当用非傍轴方法处理.     

高斯光束的象差平衡

本文从有象差时的衍射积分出发,导出高斯光束中心点亮度与波象差方差的关系,依据斯特列尔判据,采用解线性方程组的方法讨论了高斯光束球差及轴外象差的最佳校正形式,并以表格方式给出了最佳校正形式.     

高斯积分在量子表象理论中的应用

首先证明了真空投影算符的正规乘积形式,然后结合有序算符内积分技术,把数学上的高斯积分推广到量子算符的积分形式.通过表象的完备性与对称性,进一步给出了坐标表象、动量表象、中介表象和相干态表象的具体形式.     

高斯型超声换能器及其线性与非线性声场

本文介绍了一种具有独特性能的高斯型声场。声场的分析包括线性与非线性。同时对产生这种高斯型声场的高斯型超声换能器的当前研究也作了介绍与评述。文章也指出了高斯型换能器在超声检测中的应用前景。     

非傍轴矢量高斯光束单缝衍射的严格理论

提出非傍轴矢量光束衍射严格的电磁场理论,并以非傍轴矢量高斯光束的单缝衍射为例加以说明.与基于矢量瑞利-索末菲衍射积分推出的解析结果做了数值计算比较,表明了二者的一致性.对理论的进一步推广做了简要讨论. 关键词： 严格的电磁场衍射理论 矢量瑞利-索末菲衍射积分 非傍轴矢量高斯光束的单缝衍射     

拉盖尔-高斯截断级数展开法的应用

 用拉盖尔-高斯截断级数模拟了任意半径的圆孔硬边光阑窗口函数,并应用于研究高斯光束和零阶贝塞尔-高斯光束通过硬边光阑的衍射。对高斯光束和零阶贝塞尔-高斯光束的轴向和横向光强分布的计算结果表明：当积分面不是很靠近光阑时，用参数最佳化选取的拉盖尔-高斯截断级数法与用直接数值积分所得结果符合很好。     

一维线阵离轴高斯光束通过湍流大气的传输特性

研究了一维(1D)线阵离轴高斯光束通过湍流大气的传输特性，推导出了其光强传输方程. 研究表明，1D线阵离轴高斯光束通过湍流大气传输经历了三个阶段，即在近场其光强分布为类似于入射光的锯齿状分布，随着传输距离的增加逐渐变为平顶分布，最后在远场成为类高斯分布. 湍流的增强会使光束传输经历三阶段的进程加快. 并且，湍流使得不同子光束数的1D线阵离轴高斯光束的归一化光强分布相接近. 此外，子光束数越多的1D线阵离轴高斯光束受到湍流的影响越小；1D线阵离轴高斯光束较高斯光束受到湍流的影响要小. 关键词： 一维(1D)线阵离轴高斯光束 湍流大气 传输特性     

Application of Novel Focusing Mirrors in Gyrotron Transmission Lines

A novel focusing mirror based on the shifting of the beam phase according to the Gaussian beam optics enabled us to realize a focusing elements with different focal lengths in different directions and to convert the gyrotron output into a Gaussian-like beam. In this paper, we compare the quality of beams produced by the new system (which includes novel mirrors) and a conventional system consisting of a quasi-optical antenna, an ellipsoidal mirror and two parabolic cylinder mirrors.     

On the stable evolution of squeezed and correlated states

It is shown that the stable evolution equations for the squeezed and correlated states (SS and CorS) in the form of H_w × SU (l.l)-coherent states with maximal symmetry are classical Hamiltonian equations with a Kaehler symplectic 2-form of Onofri type. The evolution of the second momenta of the Hermitian quadratures of the boson operator is described by canonical equations. The general form of the Hamiltonian which correlates without squeezing is found and the connection of the stable evolution of SS and CorS with the existence of linear integrals of motion is pointed out.Presented at the International Workshop on Squeezed and Correlated States in Quantum Optics, Moscow, December 3–7, 1990.     

双频回旋管内置准光模式变换器设计

回旋管一般使用准光模式变换器实现高阶腔体模式到高斯波束的转换。结合标量衍射理论、KS迭代算法、几何光学、最小均方法等方法设计了工作频率为140 GHz(TE24,9)和105 GHz(TE18,7)的双频准光模式变换器。仿真结果显示所设计的准光模式变换器工作频率为140 GHz(TE24,9)时能量传输效率99.0%、高斯含量99.7%,工作频率为105 GHz(TE18,7)时能量传输效率97.3%、高斯含量98.0%。能够满足MW级双频回旋管的应用需求。     

Coincidence Imaging and interference with coherent Gaussian beams

we present a theoretical study of coincidence imaging and interference with coherent Gaussian beams. The equations for the coincidence image formation and interference fringes are derived, from which it is clear that the imaging is due to the corresponding focusing in the two paths. The quality and visibility of the images and fringes can be high simultaneously. The nature of the coincidence imaging and interference between quantum entangled photon pairs and coherent Gaussian beams are different. The coincidence image with coherent Gaussian beams is due to intensity-intensity correspondence, a classical nature, while that with entangled photon pairs is due to the amplitude correlation a quantum nature. Selected from Acta Sinica Quantum Optica, 2005, 11(4)(in Chinese)     

Quantum entanglement and nonlocality properties of two-mode Gaussian squeezed states

Quantum entanglement and nonlocality properties of a family of two-mode Gaussian pure states have been investigated. The results show that the entanglement of these states is determined by both the two-mode squeezing parameter and the difference of the two single-mode squeezing parameters. For the same two-mode squeezing parameter, these states show larger entanglement than the usual two-mode squeezed vacuum state. The violation of Bell inequality depends strongly on all the squeezing parameters of these states and disappears completely in the limit of large squeezing. In particular, these states can exhibit much stronger violation of local realism than two-mode squeezed vacuum state in the range of experimentally available squeezing values.     

非傍轴矢量高斯光束的圆屏衍射

利用矢量瑞利衍射积分公式，推导出非傍轴矢量高斯光束圆屏衍射的解析表示式.非傍轴矢量高斯光束圆屏衍射的轴上场分布、远场表示式、自由空间中的传输公式，以及傍轴近似下高斯光束圆屏衍射的菲涅耳和夫琅禾费衍射公式可以作为一般公式的特例统一处理.数 值计算和比较实例说明了非傍轴矢量高斯光束的光强分布和远场特性.分析表明，在圆屏衍 射中，f参数和截断参数决定光束的非傍轴行为. 关键词： 传输光学 非傍轴矢量高斯光束 圆屏衍射 矢量瑞利衍射积分公式     

Long-time evolution in the dicke model

Presented at the International Workshop on Squeezed and Correlated States in Quantum Optics, Moscow, December 3–7, 1990.     

Macroscopic Approach to Quantum Optics

This paper investigates how an approach alternative to the canonical quantization schemes may be used to describe Quantum Optics phenomena. By utilizing the approach pioneered by Keldysh, we derive equations for the time dependent correlation functions of the quantized optical fields. These contain the coupling to matter in linear and nonlinar response functions which replace the material parameters of phenomenological macroscopic theories. We present these results as alternatives to existing theoretical methods in Quantum Optics. The paper presents the general formulation of the theory, derives the equations in some specific cases relating to non‐linear optics, and solves some illustrative special cases. We regain known results but also some additional terms deriving from the quantum fluctuations of the material media.