Optical properties and structures of silver thin films deposited by magnetron sputtering with different thicknesses

A series of thin Ag films with different thicknesses grown under identical conditions are analyzed by means of spectrophotometer. From these measurements the values of refractive index and extinction coefficient are calculated. The films are deposited onto BK7 glass substrates by direct current (DC) magnetron sputtering. It is found that the optical properties of the Ag films can be affected by films thickness. Below critical thickness of 17 nm, which is the thickness at which Ag films form continuous films, the optical properties and constants vary significantly with thickness increasing and then tend to a stable value up to about 40 nm. At the same time, X-ray diffraction measurement is carried out to examine the microstructure evolution of Ag films as a function of films thickness. The relation between optical properties and microstructure is discussed.     

窄带干涉滤光片抗击不同输出方式激光的损伤特性研究

利用Nd∶YAG调Q单脉冲激光和自由脉冲激光对硬膜窄带干涉滤光片进行激光损伤阈值的测试，并且采用表面热透镜技术测量了滤光片的吸收率。实验发现:窄带干涉滤光片的吸收率和激光损伤阈值强烈依赖于辐照激光波长与窄带干涉滤光片通带的相对位置；在调Q单脉冲激光作用下，不同中心波长的滤光片损伤形貌存在明显的差别，而在自由脉冲激光作用下，各滤光片的损伤形貌则趋于相同，均表现为典型的热熔烧蚀破坏。根据实验结果，结合损伤形貌，通过驻波场理论对激光作用下滤光片内电场分布的分析与模拟，探讨了两种激光模式作用下滤光片的损伤特征和损伤机理的不同特点。     

沉积温度对HfO2薄膜残余应力的影响

 用电子束蒸发方法制备了HfO₂薄膜，根据镀膜前后基片曲率半径的变化，用Stoney公式计算了薄膜应力，讨论了沉积温度对薄膜残余应力的影响。结果发现，HfO₂薄膜的残余应力均为张应力，应力值随沉积温度的升高先增大后减小，在280 ℃左右出现极大值。对样品进行了XRD测试，从微观结构上对实验结果进行了分析，发现微结构演变引起的内应力变化是引起薄膜残余应力改变的主要因素，HfO2薄膜在所选沉积温度60~350 ℃内出现了晶态转变，堆积密度随温度升高而增大。     

Antireflective characteristics of triangular shaped gratings

It is well known that conventional multi-layers are oftenused for antireflective coatings[1,2]. There are, however,only a handful of optical materials available, thus limit-ing the performance that could ideally be achieved. Onthe other hand, sub-wavelength structure surfaces, whichare surface-relief gratings with periods smaller than theincident wavelength, have been researched and foundto have antireflective properties[3,8]. Compared withstandard optical thin-film coating technologies, the h…     

用Laurent级数展开法化有理分式为部分分式

将函数Laurent展开定理及留数概念应用于有理分式得到将有理分式化为部分分式的一种行之有效的方法.     

磁控反应溅射法制备渐变折射率薄膜的模型分析

阐述了磁控反应溅射法制备渐变折射率薄膜的机理;探讨了磁控反应溅射法制备渐变折射率薄膜的理论模型,给出了渐变折射率薄膜的折射率与反应气体分压的关系,在一定的沉积参数下,由要得到的膜层折射率随膜层几何厚度的变化规律可推导出反应气体分压比随时间的变化规律;最后以制备折射率线性变化的薄膜为例说明了如何推导得到反应气体分压比随时间的变化规律. 关键词： 渐变折射率 磁控反应溅射 模型     

Effects of oxygen partial pressure on optical absorption edge and UV emission energy of ZnO films

ZnO, with a band-gap of 3.37 eV and a large exciton binding energy (about 60 meV) at room temperature, is a promising material for optoelectronic devices, field- emission displays, and gas sensors. Recently, the interest in short wavelength display device is on the increase. In this regard, ZnO is a promising material[1-6]. High quality ZnO films have been prepared by many methods such as sputtering[7], reactive thermal and electron-beam evaporation[8], pulse laser deposition[9], chemical v…     

Newly designed multilayer thin film mirror for dispersion compensation in Ti:sapphire femtosecond lasers

There are two different effects to generate group delay dispersion by multilayer thin film mirrors: chirper effect and Gires-Tournois effect. Both effects are employed to introduce desired dispersion in the designed mirror. Thus the designed mirror provides large dispersion throughout broad waveband. Such mirror can be used for dispersion compensation in Ti:sapphire femtosecond lasers. Most group delay dispersion of a 5-mm Ti:sapphire crystal can be compensated perfectly with only four bounces of the designed mirror.     

负离子元素杂质破坏模型

探讨了HfO₂薄膜中负离子元素杂质破坏模型，并得出薄膜中的杂质主要来源于 镀膜材料. 用电子束蒸发方法沉积两种不同Cl元素含量的HfO₂薄膜，测定薄膜 弱吸收和损伤阈值来验证负离子元素破坏模型. 结果表明，随着Cl元素含量的增加薄膜的弱 吸收增加损伤阈值减小. 这主要是因为负离子元素在蒸发过程中形成挥发性的气源中心而产 生缺陷，缺陷在激光辐照过程中又形成吸收中心. 因此负离子元素的存在将加速薄膜的破坏 . 关键词： 负离子元素杂质 缺陷 吸收     

Ising自旋体系的非平衡动态相变

在平均场理论架构下, 以含时金兹堡-朗道和Glauber动力学这两类动态模型为基础，研究 了受外场和温度共同驱动的Ising自旋体系的非平衡动态相变.确定了界定动态无序(动态顺 磁相P)和动态有序(动态铁磁相F)转变的动态相界.并根据动态序参量Q和Binder参数U随系统 温度t(r₀)、驱动外场频率ω和振幅h₀的变化规律，就上述两类模 型的动态相界上是否存在区分连续动态转变和非连续动态转变的三临界点这一引发争议的问 题做出了进一步分析说明. 关键词： Ising自旋体系 非平衡动态相变 含时金兹堡-朗道模型 Glauber 动力学模型