椭偏法测量表面微粗糙合金钢材料的光学常数研究

采用椭偏法测量入射光波长为0.632μm,入射角为50°～85°时合金钢的光学常数。考虑材料表面的粗糙度,用Ohlidal-Lukes理论对所测光学常数值进行了修正,发现椭偏参量的修正量随入射角增大而增大。结果表明,测量入射角在50°～70°范围内测量值与修正后计算结果基本一致,在70°～85°范围内测量值与修正后的计算结果差距较大。因此,用椭偏法测量合金钢光学常数时使入射角小于70°,测量结果会更加准确。     

金刚石压砧内单晶硅高压折射率的椭偏测量

针对高压对顶砧入射角度受限、样品微小的特殊测量条件，设计原位椭偏测量系统，实现450～700 nm光谱范围的小角度椭偏测量。建立光学模型，获得2～9 GPa下单晶硅的折射率，发现单晶硅的折射率随压力增加而增大。与高压拉曼光谱的对比说明椭偏法原位监测材料光学性质变化的可能性。本文研究可为高压下材料的光学常数及其原位测量提供有益补充。     

多功能椭偏测厚仪

研究成功一台变入射角反射式消光法多功能智能椭偏测厚仪。实验表明 :仪器的测厚准确度为± 0 1nm ;椭偏参数Ψ和Δ的测量重复性精度分别为± 0 1°和± 0 3° ,适用于纳米级薄膜厚度和折射率的测量     

双层光学薄膜参数的多入射角椭偏分析方法

本文讨论了多入射角椭偏测量中光学参数的误差因子以及最佳测量条件的选取.指出,当薄膜较厚时,多入射角椭偏测量可以精确确定膜系的光学常数和几何厚度,并用二例实测结果加以证实.本文的方法也适用于分析多层光学薄膜.     

椭圆偏振法测定在线Low-E玻璃的可见-近红外光学常数与膜厚

从在线Low-E玻璃光学机理出发,用椭圆偏振光谱仪对在线Low-E玻璃功能层和过渡层的可见-近红外波段的光学常数进行研究.测量了样品在三个不同入射角的椭偏参数,分别用Lorentz双振子模型和Cauchy模型来描述Low-E玻璃功能层和过渡层的光学色散特性.通过拟合椭偏参数获得在线Low-E玻璃的光学常数及每层膜厚度,并用扫描电镜对样品的膜厚进行表征.结果表明,Lorentz双振子模型和Cauchy模型能很好地解释在线Low-E玻璃的光学特性;同时,椭圆偏振法也为多层膜系统提供了一种测定光学常数和膜厚的可靠方法.     

椭偏光谱测量中椭偏参数的灵敏度分析

在对椭圆偏振测量的基本原理进行了简单介绍和推导后,讨论了椭圆偏振测量中椭偏参数关于薄膜参数的灵敏度以及入射角对椭偏参数的影响,并进行了具体的仿真分析,得到如下结论：椭偏参数Delta对薄膜光学常数和薄膜厚度变化的灵敏度明显高于椭偏参数Psi。在椭偏数据处理中,椭偏参数Delta的测量精度直接影响薄膜光学常数和薄膜厚度的拟合精度。为了提高椭偏参数Delta的测量精度,可以选择入射角在膺布儒斯特角附近。所得结论对高精度椭偏测量具有指导意义。     

类金刚石薄膜光学常数拟合模型的合理性研究

由于椭偏光谱测量结果不能直接反映所测量样品材料的结构和光学性质，所以需要利用最小二乘法来拟合分析椭偏光谱数据得到光学常数。而椭偏光谱分析依赖于构建的模型，且可能存在多模型解，因此考虑模型的合理性就显得十分必要。本文采用椭偏法测量了类金刚石薄膜(DLC)的光学常数，分析并拟合了脉冲真空电弧离子技术镀制的类金刚石薄膜的椭偏光谱．获得了光学常数，并对拟合模型的合理性和测量结果的可靠性进行了分析。     

椭偏与光度法联用精确测定吸收薄膜的光学常数与厚度

介绍了一种同时利用椭偏仪和分光光度计精确测量薄膜光学常数的方法, 并详细比较了该方法与使用单一椭偏仪拟合结果的可靠性.采用可变入射角光谱型椭偏仪（VASE）表征了250—1700 nm波段辉光放电法沉积的类金刚石薄膜,研究发现当仅用椭偏参数拟合时,由于厚度与折射率、消光系数的强烈相关性,无法得到吸收薄膜光学常数的准确解.如果加入分光光度计测得的透射率同时拟合,得到的结果具有很好的惟一性.该方法无需设定色散模型即可快速拟合出理想的结果,特别适合于确定透明衬底上较薄吸收膜的光学常数. 关键词： 光学常数 光谱型椭偏仪 吸收薄膜 透射率     

多样品法确定类金刚石薄膜的光学常数与厚度

采用乙烷气体辉光放电法在单晶Si衬底上制备了名义厚度分别为75,150和250nm的类金刚石碳(DLC)薄膜,除沉积时间外其他工艺参数完全一致。使用可变入射角光谱型椭偏仪(VASE)测量了380～1700nm波段的椭偏谱。该研究发现,对单一DLC样品的椭偏数据进行分析时,一定的范围内,假定不同的薄膜厚度均可以得到非常好的拟合结果。结果表明,采用单样品椭偏法拟合时,厚度与光学常数呈现出强烈的关联性,无法快速获得准确的结果。采用多样品椭偏法,对三个样品建立相同的物理模型,假定他们的光学常数相同,进行数据拟合。分析发现该方法可以快速、简便地获得精确的折射率、消光系数以及厚度值。经过检验,结果具有非常好的唯一性。     

椭偏与光度法联用精确测定吸收薄膜的光学常数与厚度

介绍了一种同时利用椭偏仪和分光光度计精确测量薄膜光学常数的方法, 并详细比较了该方法与使用单一椭偏仪拟合结果的可靠性.采用可变入射角光谱型椭偏仪（VASE）表征了250—1700 nm波段辉光放电法沉积的类金刚石薄膜,研究发现当仅用椭偏参数拟合时,由于厚度与折射率、消光系数的强烈相关性,无法得到吸收薄膜光学常数的准确解.如果加入分光光度计测得的透射率同时拟合,得到的结果具有很好的惟一性.该方法无需设定色散模型即可快速拟合出理想的结果,特别适合于确定透明衬底上较薄吸收膜的光学常数.     

Fatigue damage rule of LY12CZ aluminium alloy under sequential biaxial loading

A series of biaxial two-level variable amplitude loading tests are conducted on smooth tubular specimens of LY12CZ aluminium alloy.The loading paths of 90°out-of-phase,45°out-of-phase and 45°in-phase are utilized.The fatigue damage cumulative rules under two-level step loading of three loading paths are analyzed.By introducing a parameter which is a function of the phase lag angle between the axial and the torsional loading,a new multiaxial nonlinear fatigue damage cumulative model is proposed.The proposed model is evaluated by the experimental data for two-level loading,multi-level loading of LY12CZ aluminium alloy,and multi-level loading of 45 steel.Fatigue lives predicted are within a factor of 2 scatter band.     

New lead-free solder alloy

As the electronics industry is moving towards lead-free manufacturing processes, a new lead-free solder alloy based on Sn–9Zn–1Bi–2Cu–In is described. The quaternary alloy with indium additions exhibits melting, wetting, and mechanical properties superior to those in binary, ternary, and quaternary alloys. Indium as a penternary addition decreases the melting point of this alloy to 181 ^°C which it is a lower value when compared with the eutectic Sn–Pb solder (183 ^°C), it decreases the contact angle to 23^° which is very close to that for Sn–Pb solder alloy, it increases the Young’s modulus to higher values, and it increases its hardness to 19 kgf/mm² when compared with 12.9 kgf/mm² for the Sn–Pb solder alloy.     

一种改进型菲涅尔棱体的设计与分析

通过对光学材料和器件内全反射角的优化设计，提出一种改进型菲涅尔棱体模型，使入射光在器件内以相同的内反射角θ在两种不同玻璃材料和空气构成的界面上发生两次全反射，由反射引起的相位延迟的变化可以相互补偿，从而设计出对入射角不敏感的相位延迟器.计算表明，入射角变化±2°时，该相位延迟偏差不超过0.36°，且保持了原型菲涅尔棱体正入射和正出射的优点，大大方便了使用. 关键词： 相位 全内反射角 折射率     

Ellipsometric studies of polished silicon surfaces

The optical constants of mechanically polished silicon surfaces were determined at λ = 546.1 nm applying the least squares method to the ellipsometric parameters ψ and Δ studied as functions of angle of incidence in the interval 〈70°, 80°〉. These optical constants differ considerably from those of Si single crystal. For all polished samples studied the indices of refraction spread over the interval 〈4.11, 5.43〉 and the indices of absorption spread over the interval 〈0.05, 1.90〉. Possible physical models of the thin surface layer of Si which was damaged during the mechanical polishing are qualitatively discussed.     

用于高能啁啾脉冲压缩的光子晶体光栅的设计

 为了克服目前高能短脉冲装置压缩光栅的损伤阈值无法满足要求的问题,针对星光Ⅲ装置皮秒激光束的压缩器,设计了由熔石英材料构成的、具有较高损伤阈值的光子晶体光栅,该光栅由2维光子晶体和表面光栅结构两部分组成,具有高反射效率和强角色散的能力。计算结果显示:经过优化设计的光子晶体光栅在波长1 053 nm,57°～77°的入射范围内,-1级衍射效率超过了92%,而当入射角为71°时,在1 040～1 090 nm光谱范围内,-1级衍射效率超过92%,性能满足使用要求。     

铝球弹丸超高速斜撞击薄铝板特性研究

 利用2017铝合金球形弹丸超高速斜撞击2A12铝合金薄板,模拟空间碎片对航天器防护屏的超高速撞击作用。分析了铝合金薄板超高速斜撞击穿孔特性与弹丸滑弹返溅特性,建立了铝合金球形弹丸超高速斜撞击铝合金薄板的穿孔经验公式。弹丸撞击速度分别为2.58、3.56和4.31 km/s,撞击角度为10°~80°。实验结果表明：铝合金薄板超高速斜撞击椭圆穿孔尺寸与撞击速度和撞击角度有关,直径为3.97 mm的铝合金球形弹丸超高速斜撞击厚度为1 mm的铝合金薄板时,发生滑弹返溅的临界撞击角在30°~40°之间。最大滑弹返溅角随着撞击角的增大而逐渐减小,此时滑弹返溅碎片云的影响范围缩小,但破坏能力增强。弹丸撞击速度对铝合金薄板超高速斜撞击穿孔的椭圆度影响较小。     

Synchrotron far‐infrared spectroscopy of corroded steel surfaces using a variable angle of incidence

Far‐infrared spectroscopy, using a synchrotron source, has been used to study carbon steel corroded in CO₂‐saturated brine in the presence and absence of the corrosion inhibitor 2‐mercaptopyrimidine (MPY), which allowed the steel surface roughness to be modified. The effect of the angle of incidence (θ_i, 30–80°) on the band intensity and observed bands of the spectra from these surfaces has been determined. For the MPY‐treated steel (low surface roughness) the highest band intensity is observed at high θ_i (80°) and different bands were observed at different θ_i. In contrast, for the MPY‐free steel (high surface roughness) the highest band intensity is observed at low θ_i (30°) and spectral content changes were not observed. The results are explained in terms of the roughness of the MPY‐treated and MPY‐free steels, and their effect on the level of diffusely reflected light of the incident infrared beam.     

Experimental study of surface and bulk plasmon losses induced in Al(001) by low energy electrons

We have measured the relative intensity of the elastic peak, and of the surface and bulk plasmon loss peaks, for electrons backscattered from an Al(001) single crystal surface. The exciting beam has an energy between 100 and 2000 eV, and impiges on the surface in an high symmetry plane of incidence with a colatitude angle of incidence varying between 0° and 80°. In a first series of experiments called “angle integrated experiment”, all the backscattered electrons are collected in a 2π solid angle retarding field analyser as a function of the primary beam energy and colatitude angle of incidence. In a second series called “angle resolved experiment”, the acceptance angle of the detector is set at 10° or $\text{1}\text{2}\text{°}$ and the variable parameters are colatitude angles of incidence and emission. We observe mainly that very clean aluminum exhibits large plasmon loss peaks with a negligible background. The results cannot be accounted for without sophisticated models, but “angular resolved experiments” are more suitable for a simple discussion than the “angle integrated experiment” and show mainly the phonon-plasmon coupling plus a θ dependent creation probability.     

Numerical study of the extinction matrix for a plate crystal

Energy and polarization characteristics of optical radiation passed through a semitransparent plate crystal with a preset orientation in space are studied numerically within the framework of the method of physical optics. Results of calculations of the extinction matrix elements versus particle size, refractive index, crystal orientation, and incident radiation wavelength (from 0.5 to 15 μm) are presented. It is demonstrated that K₁₁, K₁₂, and K₃₄ are most informative among the elements of the extinction matrix. It is established that the first of them is most sensitive to changes in the microphysical and orientational parameters of the particle when the angle of radiation incidence on the plate changes from 0 to 20°, and the nondiagonal elements are most sensitive when the angle of radiation incidence is greater than 40°. The characteristics of the total field scattered near the forward direction are determined. It is established that their dependence on the physical parameters of the crystal is most strong at scattering angles smaller than or equal to 4° and wavelengths from the IR range (in particular, from the atmospheric transparency window).