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1.
WANG Zhanshan WANG Fengli ZHANG Zhong CHENG Xinbin QIN Shuji & CHEN Lingyan Institute of Precision Optical Engineering Department of Physics Tongji University Shanghai China 《中国科学G辑(英文版)》2005,48(5):559-574
With the development of the multiplayer technology, the multilayer mirrors have been widely used in many fields, such as the soft X-ray astronomical telescope, soft X-ray microscopy, extreme ultraviolet lithography, applications of synchrotron radiation, plasma diagnosis, and so on. However, in the hard X-ray region, especially for the wavelength shorter than 0.1 nm, the optical elements based on the traditional multilayers or the single high-Z metal coatings cannot accommodate the advancemen… 相似文献
2.
介绍了一种可应用于X射线Kirkpatrick-Baez(KB)显微镜的光学元件—X射线超反射镜。选用的W和B4C作为镀膜材料,膜对数为20,采用单纯型调优的方法实现了X射线超反射镜设计,用磁控溅射的方法在Si基片上完成了W/B4C X射线超反射镜的制备。采用高分辨率X射线衍射仪(8 keV)测量了X射线超反射镜的反射特性。制备的X射线超反射镜在掠入射角分别为1.052°和1.143°处,反射角度带宽为0.3°,反射率达到20%,可满足KB型显微镜的要求。 相似文献
3.
阐述了利用非均匀膜系理论设计宽角度多层减反射薄膜的方法 ,从理论上分析了在宽角度的情况下 ,偏振光产生透过率不同的原因 ,选取了Ta2 O5和SiO2 两种材料作为折射率材料 ,选取BK7作为基底材料模拟设计了光谱区在 6 0 0~ 70 0nm波段、入射角为 0°~ 80°之间的宽角度多层减反射薄膜 ,探索出了一条新型膜系设计的途径 ,其优化结果是较为理想的。这一研究方法如能在太阳能、光纤通信、航天、激光等领域应用 ,将大大地提高光能的利用率 ,具有重要的应用价值。 相似文献
4.
V. P. Afanas’ev A. V. Lubenchenko S. D. Fedorovich A. B. Pavolotskii 《Technical Physics》2002,47(11):1444-1452
The energy spectra of electrons reflected from multilayer targets are studied theoretically and experimentally. A self-consistent theory of electron reflection from multilayer surfaces is constructed. Simple analytical models of electron reflection that illustrate the feasibility of the depth profiling of multilayer targets are presented. The energy spectra of electrons normally incident on Nb/Si and Nb/Al/Nb/Si targets and reflected from them at an angle of 45° to the normal are taken. A method for the depth profiling of such structures is elaborated. 相似文献
5.
粒子群优化算法是一种新的演化计算技术,与遗传算法相比,粒子群优化算法具有易于实现,控制参量少等优点,且在大多数的情况下,可快速收敛于最优解.为了获得更优的膜系结构,本文提出了一种利用粒子群优化算法进行膜系设计的方法,并以增透膜、高反膜及分光膜为优化设计实例验证该方法的可行性.在这些实例中,以理论反射率和实际反射率的误差平方和为评价函数.结果表明,将粒子群优化算法用于膜系设计是有效的,在相同设计条件下,应用粒子群优化算法可以得到比遗传算法更优的膜系结构. 相似文献
6.
Determination of Tungsten Layer Profiles in Bilayer Structures Using X-Ray Reflectivity Method 总被引:1,自引:0,他引:1
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An effectual method is presented to determine the profiles of a tungsten (W) layer, such as the density, the thickness and the roughness in the multilayer structures, using the x-ray reflectivity technique. To avoid oxidation effects of tungsten, a B4 C capping layer is deposited onto to the W layer. To observe the profiles of the tungsten layer with different thicknesses, three groups of W/B4 C bilayers with different thicknesses are prepared by using ultra high vacuum dc magnetron sputtering and measured by an x-ray diffractometer. A type of genetic algorithm called the differential evolution is used to simulate the measurement data so as to obtain the parameters of bilayers. According to the simulation, it is shown that the W layer density varies from 95.26% to 97.51% compared to the bulk. In our experiment, the deposition rate is 0.044 nm/s, and the thickness is varied in the range of 9.8-19.4 nm. 相似文献
7.
S.M. Al-Marzoug 《Optics Communications》2006,265(1):234-240
Designing multilayer optical coatings is a difficult optimization problem because of the huge size of the search space. In the present paper, the Luus-Jaakola (LJ) optimization procedure, a new optimization algorithm, is employed to model multilayer optical coatings in the X-ray domain. With this algorithm it is not necessary to specify initially the number of layers present in a design. Only an upper limit needs to be defined. The algorithm has been used to maximize the reflectivity over a range of incident angles at a fixed wavelength, and over a wavelength range at a fixed incident angle. The results show that the LJ algorithm can be effectively applied to the design of multilayer optical coatings resulting in fewer layers than obtained using alternative optimization methods. 相似文献
8.
A new method for improving polarizing neutron coatings has been verified experimentally. This method is based on the use of
Ti interlayers with a negative potential (“antibarrier layers”) at interfacial layers of a polarizing coating for suppressing
reflections of neutrons with the undesired spin. It can be expected that the further development of the method will lead to
the creation of polarizing neutron supermirrors and multilayer monochromators of a new generation with flipping ratios up
to 103. The neutron optics based on these superpolarizing coatings not only will improve the performance and thus extend the range
of applications of polarizing devices but also can be the basis for the design of novel neutron instrumentation. 相似文献
9.
D.G. Merkel Z.E. HorváthD.E. Sz?cs R. Kovács-MezeiG.Gy. Kertész L. Bottyán 《Physica B: Condensed Matter》2011,406(17):3238-3242
Magnetic supermirrors are widely used in polarized neutron applications. A key issue in producing these multilayer structures is to avoid residual stress in the layers, which may cause the layers to peel off. In this work He+ ion irradiation of 500 keV energy was applied at fluences of 1, 24, 50, 100×1014 ions/cm2 with the aim of reducing residual stress. Structural, magnetic and neutron-optical properties were investigated by grazing incidence high-angle X-ray diffraction, magneto-optical Kerr effect, conversion electron Mössbauer spectroscopy and polarized neutron reflectometry. We find a monotonous decrease of the tensile stress upon irradiation from 1.76 to 0.37 GPa with a coupled decrease of neutron reflectivity at the critical angle and decrease of the maximum polarizing efficiency from 23% to 4% at the highest fluence compared to the as-prepared reference supermirror. The supermirrors exhibit a superposition of uniaxial and fourfold in-plane magnetic anisotropy. 相似文献
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基于模拟退火算法的宽角度X射线超反射镜设计研究 总被引:4,自引:0,他引:4
应用于硬X射线波段的宽带多层膜光学元件———宽角度X射线超反射镜的设计可以归结为一个连续变量的多维多极值的全局优化问题。缺少一种有效的全局优化方法是阻碍解决这一难题的一个关键。模拟退火算法是一种简单而且通用的全局优化算法。结合光学多层膜的设计原理提出了利用模拟退火算法来进行宽角度X射线超反射镜设计的新方法。结合已有的方法选择了W和C作为膜层的膜对材料,设计出Cu的Kα线处角度范围0.9°~1.1°反射率达到20%的宽角度X射线超反射镜。并在此基础上采用改进的自适应模拟退火算法实现了Cu的Kα线处宽角度X射线超反射镜的理想设计结果。设计结果表明了模拟退火算法在多层膜最优化设计领域的正确性和有效性。 相似文献
13.
M.V. Kirov Author Vitae 《Physica A》2009,388(8):1431-1445
A new method for the combinatorial optimization of quasi-one-dimensional systems is presented. This method is in close analogy with the well-known transfer-matrix method. The method allows for the calculation of the lowest energy levels of the system. However, when finding the ground and some low-lying states of large complex systems, this method is more economical when compared to the standard transfer-matrix method. The method presented here is based on max-plus algebra, which has maximization and addition as its basic arithmetic operations. For the explanation of this method we use cyclic water clusters as simple examples. The efficiency of the max-plus-algebraic method is demonstrated in the course of global combinatorial optimization of hydrogen bond arrangements in large polyhedral water clusters with fixed positions of the oxygen atoms. The energy of the clusters is estimated using approximate discrete models for the intermolecular interactions. 相似文献
14.
S.M. Al-Marzoug 《Optics Communications》2006,268(1):84-89
The design of hard X-ray optics for astrophysical technology is one of the key technologies for investigating active galaxies and clusters of galaxies. In the present paper, we have optimized multilayer mirrors of platinum-carbon layer pairs for the hard X-ray region at different grazing angles. The Luus-Jaakola optimization procedure has been implemented for the global optimization of multialyer mirrors. With this algorithm it is not necessary to specify initially the number of layers present in a design. 相似文献
15.
Analytical solution for multilayer assembly including heating and cooling cycles with laser pulse parameter variation 总被引:1,自引:0,他引:1
Laser heating of surfaces is involved with heating and cooling cycles. Material response to a laser pulse in the heating cycle is rapid while in the cooling cycle it is gradual. In this case, temperature rises rapidly in the heating cycle while temperature decay is gradual in the cooling cycle. Depending on the laser pulse properties (pulse length and intensity), the rise and fall of temperature profiles change in the surface region of the substrate material. In the present study, an analytical solution for laser heating pulse is presented and a closed-form solution for temperature distribution inside the multilayer assembly is obtained. Steel is considered as top layer while copper is situated below steel in the multilayer assembly. It is found that the analytical solution agrees well with the numerical predictions. Temperature rise in steel is higher than copper. This is due to the thickness of steel, which is larger than the absorption depth. In this case, internal energy gain dominates over the heat conduction in the energy transport process. 相似文献
16.
A method of simulated annealing in optimization of a computer generated holo-gram(CGH)is presented.The characteristics of energy in annealing curve are analyzed.Thecooling schedule such as giving an initial temperature,the temperature function,the numberof interactions and stopping criterion are discussed.As an example,an optimization of phaserelief kinoform,a CGH with multiple phase levels,is implemented. 相似文献
17.
粒子群优化算法是一种新的演化计算技术,与遗传算法相比,粒子群优化算法具有易于实现,控制参量少等优点,且在大多数的情况下,可快速收敛于最优解.为了获得更优的膜系结构,本文提出了一种利用粒子群优化算法进行膜系设计的方法,并以增透膜、高反膜及分光膜为优化设计实例验证该方法的可行性.在这些实例中,以理论反射率和实际反射率的误差平方和为评价函数.结果表明,将粒子群优化算法用于膜系设计是有效的,在相同设计条件下,应用粒子群优化算法可以得到比遗传算法更优的膜系结构. 相似文献
18.
提出了一种基于膜系误差灵敏度控制的鲁棒膜系设计方法,建立了鲁棒膜系设计评价函数在膜层参数误差统计分布下的解析表达式,避免统计样本数目有限性造成的样本均值与总体期望的误差,以及过大数目样本造成的长的计算时间消耗,并通过宽带增透膜、中性分光膜和线性透射率滤光片等多种薄膜的鲁棒设计实验证实了其在膜层参数误差控制上的效果。结果表明:该新型鲁棒膜系设计方法具有内在的快速算法特性,其设计膜系对镀膜中的膜厚监控误差不敏感,对于高质量薄膜的重复制备和批量成品率的提高具有实用价值。 相似文献
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本文提出一种计算相变型光盘膜系光学特性的方法.并以TeSbSe光记录介质为例,讨论了三层膜相变光盘的优化设计. 相似文献