Diffraction at 8-keV x-rays of Bragg-Fresnel optics

The basic elements of Bragg-Fresnel multilayer optics are multilayer gratings. In this paper, the fabrication process for the simplest Bragg-Fresnel multilayer optics is given; the diffraction measurements at 8-keV x rays of multilayer gratings are presented; and the measurement results in the diffraction spectrum are analyzed and discussed in detail. (C) 1996 Society of Photo-Optical Instrumentation Engineers.

Role of interface absorption in laser-induced local heating of optical coatings

Considering the interface absorption in optical coatings, we propose a model to simulate interface absorption. Calculations are made and the temperature field of several kinds of thin film multilayers, including those of partial reflectivity, high-reflectivity, and antireflectivity coatings are analyzed. The interface absorption is found to greatly influence the temperature distribution within multilayer coatings and to weaken the laser damage resistance of the samples. The real-time results of the photothermal deflection technique for laser induced damage to samples supports the model. (C) 1997 Society of Photo-Optical Instrumentation Engineers.

基底微缺陷对介质薄膜光学性能影响的理论研究

基于非均匀膜理论提出一种存在微缺陷的介质基底的折射率分层模型，将基底依次分为表面层、亚表面层和体材料层，其中表面层和亚面层分别等效为折射率服从统计分布的非均匀膜，将它们分别再次细分为N1和N2个子层，每一子层均视为均匀介质膜．应用光学薄膜特征矩阵法对其进行理论分析，并对单层介质膜的光学性能进行数值计算．研究结果表明：基底的表面和亚表面微缺陷改变了薄膜和基底的等效折射率，导致了准Brewster角和组合反射率与理想情形的偏离．同时这些微缺陷也改变了光在薄膜和基底中的传播特性，因此反射相移和相位差均偏离理想情

Birefringent non-polarizing thin film design

In this paper, 2 X 2 characteristic matrices of uniaxially anisotropic thin film for extraordinary and ordinary wave are deduced at oblique incidence. Furthermore, the reflectance and transmittance of thin films are calculated separately for two polarizations, which provide a new concept for designing non-polarizing thin films at oblique incidence. Besides, using the multilayer birefringent thin films, non-polarizing designs, such as beam splitter thin film at single wavelength, edge filter and antireflection thin film over visible spectral region are obtained at oblique incidence.

基于Berreman矩阵的双折射薄膜光谱响应特性计算

采用Berreman特征矩阵方法，通过数值计算研究了双折射薄膜的反射、透射等光谱响应特性。依据电磁场理论的电场分量、磁场分量的界面连续条件，推导了光波在各向异性双轴薄膜中的Berreman转移矩阵，用以分析含有各向异性介质层的复杂薄膜系统的光学性质。这些矩阵递推关系包含了界面处的多点反射，适用于一般的各向异性的多层膜系统，包括入射媒质或基底为各向异性的情况。在文中给出了各向同性入射媒质双轴各向异性膜层一各向同性基底薄膜系统的计算结果，验证了该计算方法的可行性，以此作为进一步研究各向异性薄膜和相关光学薄膜器

High-reflectance 193 nm Al2O3/MgF2 mirrors

Thin-film single layers of Al2O3 and MgF2 were deposited upon super polished fused-silica by electron-beam evaporation. The subsequent optical constants n and k were reported for the spectral range of 180-230 nm. High-reflectance dense multilayer coatings for 193 nm were designed on the basis of the evaluated optical constants and produced. The spectra of the reflectance of HR coatings were compared to the theoretical calculations. HR mirrors of 27 layers with a reflectance of more than 98% were reported. (c) 2004 Elsevier B.V. All rights reserved.

一种用于Yb：YAG激光器的波长分离膜的研制

以1030nm高反．940。980nm高透的波长分离膜作为实例，为提高该薄膜元件的波长分离效果，从膜系的优化方面做了一系列的研究。诸如采用带通滤光片的设计思想，在膜堆两侧加入了匹配层，调整膜堆的周期厚度，并用膜系设计软件对通带作进一步的优化。通过这一系列的优化设计后．利用RF双离子柬溅射工艺在BK7玻璃基底上沉积样品薄膜，并在基底背面加镀通带增透膜。结果显示，透射带在940和980nm处的透过率分别为97．73％和93．63％．反射带在1030nm的反射率为99．99％。对所制备的样品薄膜进行了激光损伤阈

不同膜层数的Mo/Si多层膜的表界面粗糙度和软X射线反射率

用磁控溅射法制备了顶层分别是Mo膜层和Si膜层的两个系列的Mo/Si多层膜，它们的周期厚度相同但是膜层数各不相同。Mo/Si多层膜的周期厚度和界面粗糙度由小角X射线衍射（SAXRD）曲线拟和得到。用原子力显微镜测量了Mo/Si多层膜的表面粗糙度。在国家同步辐射实验室测量了Mo/Si多层膜的软X射线反射率。通过理论和试验研究，发现Mo/Si多层膜的软X射线反射率主要由周期数和界面粗糙度决定，表面粗糙度对Mo/Si多层膜的软X射线反射率影响较小。

Analysis of characteristic matrix for a uniaxially birefringent thin film

As the principal section consistent with the principal plane, electromagnetic propagation in a uniaxially birefingent thin film can be described with a concise 2 x 2 characteristic matrix, in which the refractive indices of the forward and backward propagating extraordinary rays are different and dependent. In this letter, based on Huygen's construction, the refractive indices and effective optical admittances of the forward and backward propagating extraordinary rays are discussed further, and the 2 x 2 characteristic matrix is simplified. Furthermore, the input optical admittance, reflectance and transmittance of assembly is presented, just as an isotropic thin film. The result can be extended to the general case of multilayer uniaxially birefringent thin films with their optic axes in the incident plane. Copyright (c) EPLA, 2007.

8.0nm反射式偏振膜的设计和制备

讨论了软X射线反射式偏振膜的设计原理和方法,利用设计软件模拟设计了8.0nm处的Mo/B4C偏振膜.对影响多层膜性能的参量进行了详细的误差分析.利用磁控溅射镀膜机进行了偏振膜的制备研究,X射线小角衍射测量了多层膜的周期厚度,测量数据的拟合结果与设计值吻合很好.

Mo／Si软X射线多层膜的界面粗糙度研究

用磁控溅射法分别制备了以Mo膜层和Si膜层为顶层的Mo／Si多层膜系列，利用小角X射线衍射确定了各多层膜的周期厚度。以不同周期数的Mo／Si多层膜的新鲜表面近似等同于同一多层膜的内界面，通过原子力显微镜研究了多层膜界面粗糙度随膜层数的变化规律。并在国家同步辐射实验室测量了各多层膜的软X射线反射率。研究表明：随着膜层数的增加，Mo膜层和Si膜层的界面粗糙度先减小后增加然后再减小，多层膜的峰值反射率先增加后减小。

多层介质膜脉冲宽度压缩光栅与超短脉冲作用时的性能分析

基于啁啾脉冲放大技术的超短脉冲激光系统是提供超快、超强激光的重要途径，具有良好输出波形和高损伤阈值的多层介质膜脉冲宽度压缩光栅是获得高峰值功率脉冲激光的关键。基于傅里叶谱变换方法和严格模式理论，分析了多层介质膜光栅（MDG）在超短脉冲作用下的光学特性。结果表明，当MDG的反射带宽小于具有高斯分布的入射脉冲的频谱宽度时，-1级反射脉冲呈非对称高斯分布，其前沿出现振荡，并且-1级反射脉冲能量开始剧烈下降，讨论了MDG结构参数对其反射带宽的影响。分析了MDG与超短脉冲作用时的近场光分布，对提高其抗激光损伤特性具

用于钕玻璃啁啾脉冲放大系统光谱整形的多层介质膜反射镜

在千焦拍瓦高功率啁啾脉冲放大系统设计中,为了尽量消除增益窄化和增益饱和效应的影响,同时尽可能提高高功率激光输出脉冲信噪比参数,激光脉冲时空和光谱的整形问题备受关注.提出一种光谱整形新方法,利用特定结构的多层介质膜反射镜,可实现对大能量高功率啁啾脉冲钕玻璃放大系统中啁啾脉冲的光谱整形.研究结果表明,只要合理选择多层介质膜系的结构参数,可有效地控制其反射率分布,且在保证反射相位基本不变的条件下其调制度可超过60%.针对钕玻璃1053nm波长设计而成的光谱整形反射镜,反射带宽可达到196nm,色分辨率约为0.1nm,在几十纳米波长范围所对应的相位偏差小于12mrad,相当于λ/524,能够满足"神光Ⅱ"千焦拍瓦改造的技术指标要求.

Novel method for design of surface relief guided-mode resonant gratings at normal incidence

We demonstrate that the surface relief guided-mode resonant gratings with specified central wavelength and FWHM in the visible wavelength range can be designed by analyzing the complex poles of Reflectance and transmission coefficient matrix algorithm (RTCM), a variant of S-matrix propagation algorithm proposed for calculation of multilayer gratings. In addition, FWHM is computed with couple-mode (CM) theory of resonant gratings which is firstly extended by Norton et al. in calculation of waveguide grating. Furthermore, the side band reflections of the filter can be reduced to less than 5% in the visible wavelength with the antireflection (AR) design technique widely used in the thin-film field. (C) 2008 Elsevier B.V. All rights reserved.

反射型导模共振滤波器设计

导模共振滤波器由于其高峰值反射率,低旁带反射,窄带以及带宽可控等优良特性引起了人们极大的关注,采用亚波长光栅的导模共振效应可以实现传统基于高低折射率介质的多层膜滤波器所无法实现的特殊功能,在弱调制模式下,其共振带宽可以被压缩到零点几纳米,但是由于介质表面和空气层的菲涅耳反射,使得偏离或者远离共振区时的反射率偏高,根据等效介质理论,亚波长光栅在远离共振区可以被看为均匀的薄膜,本文通过对导模共振光栅进行单层、双层以及三层抗反射设计,有效的降低了导模共振光栅的旁带反射率,从而在可见光波段获得了性能优良的共振滤波器.