柱矢量光束在透射时的自旋霍尔效应

有限光束矢量特性可以由全局化的特征单位矢量和广义琼斯矢量完整地描述,特征单位矢量平行于传播轴的光束为柱矢量光束。通过这种表示理论描述了在近轴近似条件下柱矢量光束的透射情况。在透射过程中光束的特征单位矢量发生了变化,透射光束的特征单位矢量既不平行于传播轴,也不垂直于传播轴。特征单位矢量的变化导致光束产生了一个与入射面垂直的横向位移,同时这个横向位移和光束的偏振椭圆率有关,不同圆偏振态(左旋和右旋)的透射光束所产生的横向位移的方向相反。这一结果和近年来在实验中检测到的均匀偏振光束的自旋霍尔效应类似,表明柱矢量光束在透射过程后也会产生光的自旋霍尔效应。     

任意偏振态光束全反射时的侧向和横向位移

光束在电介质界面发生全反射时,实际反射光束会在入射面内相对于几何反射光束产生一侧向位移,在垂直于入射面的方向产生一横向位移。利用改进的能流法研究了任意偏振态光束发生全反射时的侧向和横向位移特性。研究表明,侧向位移的大小与入射光束的两组成部分———TE和TM偏振光的相位差无关,而与两组分的光强比密切相关,且该位移可以表示为TE和TM偏振光束各自的位移按光强的加权平均。横向位移的大小不仅与入射光束两组分的光强比相关,还与组分的相位差密切相关。另外,反射光束不仅在椭圆偏振态入射的情况下会产生横向位移,而且在TE和TM偏振态之外的其他线偏振态入射时,也会产生横向位移。     

左手材料中圆偏振光束的反常旋转特性研究

根据Whittaker标量势理论,建立了圆偏振光束的矢量传输模型.基于这一模型研究了圆偏振光束在左手材料中的反常旋转特性.通过分析光束偏振态、衍射对强度质心旋转特性的影响,发现圆偏振光束在左手材料中旋转方向反转并揭示其旋转角等于古伊相.采用分析横向能流的方法,揭示左手材料中反向的横向能流是导致反常旋转特性的主要原因.对圆偏振光束在左手材料中反常旋转特性的研究,有利于增强对左手材料中光束传输特性的认识. 关键词： 左手材料 圆偏振光束 旋转特性     

手征和运动介质界面异常光自旋霍尔效应

文章讨论了偏振高斯光束在空气-手征介质界面的反射和折射问题,发现了反射和折射光束的异常自旋霍尔效应.在某些特定的角度下,反射高斯光束重心的移动可以达到几十个波长的量级,通过调节手征参数,甚至会出现折射光重心移动方向由正到负的转变.文章还讨论了任意偏振高斯光束在空气-运动介质界面的反射和透射问题,当介质垂直于入射平面运动时,反射和透射光束的横向移动可以达到几个波长的量级,甚至在某些运动速度下可以实现移动方向正负的改变.这些研究对控制光的自旋霍尔效应提供了可能的途径.     

基于Metasurface的柱矢量光束的产生

本文提出了一种基于Metasurface产生任意柱矢量光束的方法.采用的Metasurface是在熔融石英上刻蚀空间变化的非周期光栅构成.非周期光栅会形成空变的有效双折射,从而对光场的偏振态空间分布进行调制.通过琼斯矩阵的方法分析得出这样的Metasurface可以将入射线偏振光转换为柱矢量光束,并且只需要改变入射线偏振光的偏振方向即可获得高阶庞加莱球赤道上任意一点的柱矢量光束.最后,用Metasurface搭建了一套简单、高效的柱矢量光束产生系统,实验结果与理论分析一致.     

基于圆偏振涡旋光束强聚焦的平顶光束的构成

由于圆偏振涡旋光束可以表征为柱坐标的径向矢量光束和角向矢量光束的线性叠加,因而在研究其聚焦特性时,必须考虑具有拓扑核的径向矢量光束聚焦后有角向分量和角向矢量光束聚焦后有径向分量。在修正关于圆偏振涡旋光束强聚焦公式的基础上,重新模拟计算了不同拓扑核的圆偏振涡旋光束的强聚焦特性。结果显示不仅单自旋手性的圆偏振涡旋光束聚焦能形成平顶光束,而且两束不同的自旋手性的涡旋光束的叠加聚焦也可以实现平顶光束。通过调节光束的振幅、束腰半径以及遮挡通光孔径可以有效地改变平顶光束的半宽。     

轴对称矢量光束聚焦特性研究现状及其应用

轴对称矢量光束是一种空间非均匀偏振光束, 中心光强为零, 经物镜聚焦后能在焦点附近产生空间场分量. 在高变迹系数光学系统成像情况下, 与线偏光、圆偏光相比, 径向偏振光与光瞳滤波技术及图像复原技术结合, 能获得较小焦斑, 提高横向分辨力. 介绍了轴对称矢量光束的特性, 基于电偶极子辐射模型和矢量衍射理论研究了轴对称矢量光束经高数值孔径物镜聚焦后的特性, 系统介绍了基于轴对称矢量光束实现光斑紧聚焦的几种方法, 并简述了轴对称矢量光束在差动共焦超分辨成像领域的研究设想. 关键词： 差动共焦显微技术 紧聚焦 光瞳滤波 轴对称矢量光束     

一种柱状矢量偏振光的检测与评价方法

针对非均匀复杂偏振光束难以用一种偏振状态描述的现象,提出了一种点对点的偏振光检测方法,该方法能够同时检测光束横向切面内所有点的偏振态,为非均匀偏振光描述提供足够的信息,解决了柱状矢量偏振光光束的质量检测问题。运用这种方法,对已知偏振光束进行验证检验取得了良好的效果,证明了该方法可以作为一种可靠、稳定的方法用对柱状矢量偏振光检测与评价。另外,一些描述柱状矢量偏振光均匀性的参数被重新定义,为柱状偏振光的质量描述提供了量化指标。     

非傍轴矢量径向偏振光束的圆孔衍射分析

本刊讯光束的矢量特性在光学检测、显微镜技术、光存储、光通讯以及激光加工等领域的作用已经进行了广泛的研究。然而这些工作大部分仅限于空间均匀的偏振光束,例如线偏振、圆偏振和椭圆偏振。2001年Gori基于琼斯矢量提出了一类非均匀偏振光束,圆柱偏振光束是其中一种特殊的非均匀偏振结构,径向偏振与角向偏振是圆柱偏振的两个本征偏振态。径向偏振光束具有轴对称的电场矢量结构和中空的环状强度分布,它经高数值孔径透镜聚焦后能够产生强度更大的电场纵向分量。     

矢量涡旋光束的生成与模式识别方法

与宏观物体类似，光子等微观粒子也可携带角动量。光子的角动量包括自旋角动量和轨道角动量，两种角动量的共同作用产生了一种新型结构光束，即矢量涡旋光束。矢量涡旋光束具有各向异性的波面和偏振分布，提供了多种光场自由度，在量子技术、光通信、激光探测、激光加工、高分辨成像、光镊等前沿领域展现了巨大的应用潜力，吸引了国内外学者的广泛关注。高效地生成矢量涡旋光束，以及高精度地识别矢量涡旋光束的模式分布，是其应用的关键。本文简要回顾了国内外学者在矢量涡旋光束的生成与模式识别方面的研究工作，同时系统梳理了本文作者过去十年在该方面的研究进展，重点介绍了其相关代表性成果。     

关于"太阳在银河系中所受引力与到银心距离r的关系"的讨论

讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系，指出引力场强g并不是与r的平方成反比，这是由于银河系的大小和形状不能忽略造成的．强调了万有引力定律的适用条件．     

On the predictability of the positions of the convergence zones in the ocean

The disagreement between the experimental and calculated positions of the first convergence zone are known from many publications. The most probable cause for such a disagreement, namely, the incorrect specification of the input data for the calculations, is considered. The lack of simultaneity between the hydrological surveys of the region and the acoustic experiments is emphasized. The experimental data obtained by the author in five ocean regions are presented. These data characterize the diurnal variability of the distance from the source to the nearest boundary of the convergence zone. The relations proposed by different researchers for calculating the sound speed from the temperature, salinity, and hydrostatic pressure are analyzed. It is shown that these relations lead to a substantial difference in the estimated depth dependence of the hydrostatic gradient of the sound speed. The position of the first convergence zone is calculated for the propagation conditions determined by vertical temperature and salinity profiles with the subsequent recalculation of these profiles into sound speed profiles by using eight different formulas known from the literature. It is shown that different formulas lead to different values of the distance to the first zone; this difference is substantially greater than that between the calculations and experiment. The necessity of improving the recalculation relations in view of the experimental data on sound propagation in natural oceanic waveguides, including the data on the actual positions of the convergence zones, is emphasized.     

On the calculation of the bremsstrahlung in the region of the plasma frequency

On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

Extracting the wavefunction of the LSP at the LHC

We consider associated production of squarks and gluinos with the lightest supersymmetric particle (LSP), or states nearly degenerate in mass with it. Though sub-dominant to pair production of color SU(3)-charged superpartners, these processes are directly sensitive to the wavefunction composition of the lightest neutralinos. Exploiting event-shape variables - including some introduced here for the first time - we are able to identify the composition of the LSP by selecting events involving a single high-pT jet recoiling against missing transverse energy. We illustrate the proposed technique on a set of benchmark cases and propose methods for applying these results in more realistic experimental environments.     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

On the Question of the Source of the Apokamp

Technical Physics - The object of this work is the apokamp—a new type of plasma jet, which is formed from a bright offshoot emerging at the bending point of a channel of a high-voltage...