单色光斜入射时光栅主极大的条数

本文证明，在不考虑缺级的条件下，单色光斜入射时光栅主极大的条数与正入射时条数之差不超过1。     

细光束斜入射时一维及正交光栅的衍射图样

一、引言众所周知,细光束正入射一维平面光栅时衍射图样成为一族直线排列、中心对称的亮点。光束斜入射,而且光束方向与光栅刻线方向并不垂直(例如二者共面)的情况,一般教材很少提及。在实际演示中,观察者常在无意中发现,这时衍射亮点的分布已不(?)同一直线上,而形成形状及曲率随观察条件而变化的弧线。对这种“非标准”条纹进行有意识的观察和分析,将会大大提高学习者的学习兴趣及增强其分析实际问题的能力。Phadke等曾就一维光栅产生的圆条纹进行过较为复杂的计算[文中某些公式,如(10)式有误],但未能具体分析光斑在弧线上的分布特点。本文将通过对物理概念和物     

高斯光束斜入射窄带滤光片的透射光强分布

基于多光束干涉原理,推导了高斯光束斜入射角度调谐窄带滤光片后的透射光强表达式.在此基础上研究了入射角对高斯光束的透射特性的影响.计算和实验结果表明:随着入射角的增大,透射光强的光斑会出现一定程度的展宽现象;当入射角度较小时,输出为单一光斑,但其光强峰值位置产生了一定的偏移,并不在呈现高斯分布;当入射角度较大时,输出则为一系列的离散光斑.     

同轴共轭透镜对斜入射平行光的聚焦衍射特性

通过对同轴共轭透镜的基尔霍夫衍射的分析,导出了合适的衍射图计算公式,分析了斜入射时的衍射图特性,给出了模拟计算和实验结果,并探讨了在调整允差方面的应用。     

倾斜入射时偏振分束棱镜的角宽压缩效应

从理论上计算了由于光束倾斜入射产生的棱镜起偏系统角谱宽度的压缩效应,计算结果表明,入射光束相对于棱镜入射面的入射角越大对角谱宽度的压缩就越明显,不同材料的基底折射率的差别对角谱宽度的压缩影响不大。通过举例从膜系设计的角度进一步论证了这一结论。还指明在实际系统中可以保持入射光束的相对角度不变的情况下,通过改变棱镜的形状来达到倾斜入射的目的从而实现角谱宽度的压缩。对如何设计出高性能的宽角宽光谱偏振分束镜具有重大的指导意义。     

高斯光束斜入射非平行法布里-珀罗干涉仪后的透射光强分布

基于多光束干涉原理,推导出了高斯光束斜入射非平行法布里-珀罗干涉仪射后的透射光强表达式,在此基础上,着重研究了高斯光束入射角的大小以及法布里-珀罗干涉仪两反射端面的不平行度对透射光强分布的影响。研究结果表明：入射角的大小和干涉仪的不平行度对透射光的强度分布、峰值强度的大小和峰值强度的位置有很大的影响;在入射高斯光束具有较小的腰斑半径或法布里-珀罗干涉仪的两端面的反射率较大时,必须考虑高斯光束沿传输轴线的衍射效应;楔角为负的非平行法布里珀罗出射光斑的光强在“反跳”处急剧下降到零,可利用这一特点对距离进行精确测量。     

斜入射光波的光栅衍射研究

本文分析了斜射光波的光栅衍射特点,并在实验中得以验证。     

一种斜入射F-P型薄膜滤光片消偏振设计方法

薄膜滤光片在斜入射使用时,s偏振光和p偏振光的特性会产生分离:两偏振光的中心波长不一致,且s偏振光的通带宽度要小于p偏振光.而采用多种材料且满足特定条件的膜系结构,可使角度入射滤光片两偏振方向的特性趋于一致.通过理论分析,建立了两偏振光反射率的表达式,由表达式可看出非偏振的条件.通过计算,求出相应材料折射率值,从而设计出消偏振的膜系.对一个三腔129层实例膜系进行了计算求解、仿真分析及误差分析.最后的结果验证表明此方法是可行的.     

斜入射激光平面靶耦合的数值模拟

LARED-H是一个柱对称二维三温非平衡辐射流体力学程序，主要用于黑腔物理研究，也可模拟正入射激光平面靶耦合过程，但无法模拟斜入射平面靶问题。实际上斜入射现象会经常发生，因此需要扩充LARED-H程序在直角坐标系下的功能，用于模拟斜入射激光平面靶耦合过程。引进拟直角坐标系，把直角坐标系与柱坐标系下的总体方程的差分格式统一，实现了直角坐标系下LARED-H程序的模拟能力。     

旋光仪的改进和实验功能拓展

设计制作了多功能旋光仪,通过光电采集系统和单片机控制电路,实现了光强的识别和记录,实现了旋转角、旋光率或溶液浓度测量结果的自动计算和显示,提高了测量的准确度和测量速度.     

Periodically structured X‐ray waveguides

The properties of X‐ray vacuum‐gap waveguides (WGs) with additional periodic structure on one of the reflecting walls are studied. Theoretical considerations, numerical simulations and experimental results confirm that the periodic structure imposes additional conditions on efficient propagation of the electromagnetic field along the WGs. The transmission is maximum for guided modes that possess sufficient phase synchronism with the periodic structure (here called `super‐resonances'). The field inside the WGs is essentially given at low incidence angle by the fundamental mode strongly coupled with the corresponding phased‐matched mode. Both the simulated and the experimental diffraction patterns show in the far field that propagation takes place essentially only for low incidence angles, confirming the mode filtering properties of the structured X‐ray waveguides.     

Error analysis and Stokes parameter measurement of rotating quarter-wave plate polarimeter

In this paper, we present a simple Stokes parameter measurement method for a rotating quarter-wave plate polarimeter.This method is used to construct a model to describe the principle of how the magnitudes of errors influence the deviation of the output light Stokes parameter, on the basis of accuracy analysis of the retardance error of the quarter-wave plate,the misalignment of the analyzing polarizer, and the phase shift of the measured signals, which will help us to determine the magnitudes of these errors and then to acquire the correct results of Stokes parameters. The method is validated by the experiments on left-handed circularly polarized and linear horizontal polarization beams. With the improved method, the maximum measurement deviations of Stokes parameters for these two different polarized states are reduced from 2.72%to 2.68%, and from 3.83% to 1.06% respectively. Our results demonstrate that the proposed method can be used as a promising approach to Stokes parameter measurement for a rotating quarter-wave plate polarimeter.     

电子束极化度测量仪及基电子学系统的研制

介绍了研制成功的电子束极化度测量仪的基本原理、结构及其电子学测量系统，该系统基于PC机的数据获取和处理，并实现了整个实验过程的自动控制，作为对电子束极化度测量仪及电子学测量系统性能的检验，实验测量了线偏振光相对Stokes参数，测量结果表明整个系统具有测量精度高、结构紧凑和性能稳定的特点。     

X‐ray spectromicroscopy with the scanning transmission X‐ray microscope at BESSY II

Using the scanning transmission X‐ray microscope at BESSY II, colloidal structures from a Chernozem soil have been studied with a spatial resolution around 60 nm and a spectral resolution of 1700 at the K‐absorption edge of carbon. Elemental mapping has been used to determine the distribution of organic matter within the colloidal structures. Spectra have been extracted from image stacks to obtain information about the chemical state. For the analysis of the latter, principal component analysis and cluster analysis have been applied. It was possible, for example, to discriminate clay particles against organic components.     

宇宙射线和α放射线的地质作用

对采集到的矿物样品结合理论计算结果进行了详细分析.阐明了矿物样品上的菱形腐蚀坑,可能是宇宙射线粒子和天然放射线中的α粒子与矿物晶格碰撞后,在晶格中留下的损伤经过地层中腐蚀性液体长期腐蚀扩大形成的.讨论了这些腐蚀坑对地质作用的影响.指出这些射线对地质作用的影响,应当是地质作用研究中不可忽视的因素.     

Characterization of an X‐ray mirror mechanical bender for the European XFEL

One of the classical devices used to tune a mirror on an X‐ray optical setup is a mechanical bender. This is often designed in such a way that the mirror is held with clamps on both ends; a motor is then used to put a torque on the clamps, inducing a cylindrical shape of the mirror surface. A mechanical bender with this design was recently characterized, to bend a 950 mm‐long mirror up to a radius of curvature of 10 km. The characterization was performed using a large‐aperture Fizeau interferometer with an angled incidence setup. Some particular and critical effects were investigated, such as calibration, hysteresis, twisting and long‐term stability.     

Feasibility of in‐line instruments for high‐resolution inelastic X‐ray scattering

Inelastic X‐ray scattering instruments in operation at third‐generation synchrotron radiation facilities are based on backreflections from perfect silicon crystals. This concept reaches back to the very beginnings of high‐energy‐resolution X‐ray spectroscopy and has several advantages but also some inherent drawbacks. In this paper an alternate path is investigated using a different concept, the `M⁴ instrument'. It consists of a combination of two in‐line high‐resolution monochromators, focusing mirrors and collimating mirrors. Design choices and performance estimates in comparison with existing conventional inelastic X‐ray scattering instruments are presented.     

Polarization control of an X‐ray free‐electron laser with a diamond phase retarder

A diamond phase retarder was applied to control the polarization states of a hard X‐ray free‐electron laser (XFEL) in the photon energy range 5–20 keV. The horizontal polarization of the XFEL beam generated from the planar undulators of the SPring‐8 Angstrom Compact Free‐Electron Laser (SACLA) was converted into vertical or circular polarization of either helicity by adjusting the angular offset of the diamond crystal from the exact Bragg condition. Using a 1.5 mm‐thick crystal, a high degree of circular polarization, 97%, was obtained for 11.56 keV monochromatic X‐rays, whereas the degree of vertical polarization was 67%, both of which agreed with the estimations including the energy bandwidth of the Si 111 beamline monochromator.     

基于双折射晶体的快拍穆勒矩阵成像测偏原理分析

针对传统穆勒矩阵成像测偏仪包含活动部件,需进行多次测量,容易产生测量误差,不能对运动目标或动态场景进行同时、实时测量等问题,提出了一种以改进型萨瓦偏光镜为核心分光器件的快拍Mueller矩阵成像测偏技术(MSP-SMMIP).它不含任何活动部件,能通过单次快拍测量获取目标强度图像和全部16个穆勒矩阵阵元图像.它主要由偏振态产生和偏振态分析两部分组成,偏振干涉条纹通过偏振态产生光路后定位于测试样品上,随后这些条纹通过空间载频将样品的Mueller矩阵分量编码,经偏振态分析光路成像于焦平面上.采用斯托克斯矢量-穆勒矩阵形式阐明了光场偏振态被MSP-SMMIP调制的过程,给出了其像面干涉图表达式,讨论了Mueller矩阵反演和系统定标的方法.基于CCD相机参数分析了系统的光学指标.通过数值模拟实验给出模拟测量结果,通过定性和定量评价测量结果表明该系统的可行性.MSP-SMMIP技术具有稳态、快拍、结构简洁、易定标、可同时实时获取目标强度图像和全部Mueller矩阵阵元图像的显著特点.