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1.
严格耦合波法计算闪耀光栅衍射效率 总被引:2,自引:0,他引:2
针对一般标量近似算法精度不高的问题,提出采用S矩阵的严格耦合波的方法计算光栅衍射效率.通过建立完整的闪耀光栅理论模型,对各分层电磁场进行傅里叶级数展开,采用散射矩阵方法求解各谐波系数,完成衍射效率计算.该方法已应用到红外光栅TE和TM 2种模式衍射效率的计算.分析了散射矩阵解决数值运算不稳定的原因,通过与标量近似计算方法进行比较,说明红外光栅衍射偏振特性. 相似文献
2.
We describe a novel optomechanical device that produces strong reflectance and polarization modulation of incident light. The structure is based on a suspended nanomechanical grating with lateral deformability, and rigorous coupled-wave analysis has been used to fully model the optical properties of the device. The grating consists of two interdigitated gratings that may be moved with respect to each other with an applied force. The structures proposed here are designed to be readily manufacturable with device processing developed for surface-micromachined microelectromechanical systems and with known microelectromechanical systems materials, such as silicon, silicon nitride, and amorphous diamond. As the spacing of the grating is changed, an anomalous diffraction effect is observed, a Wood's type anomaly in which there exists a resonance in propagating leaky modes within the grating, resulting in a dramatic change in the reflectance characteristics for slight changes in the grating. One of the unique features of this structure is that a reflected optical signal can be used to detect subangstrom in-plane motion of structures greater than 10 nm. 相似文献
3.
Based on numerical modeling of metallized diffraction gratings with multilayer insulator coatings, the diffraction efficiency of such gratings is investigated, assuming that the initial profile of the metallized grat-ing is not reproduced in the course of sequential deposition of coating layers. From comparison of experimental and calculated data, it is concluded that the initial grating relief is subject to considerable smoothing. The new nontraditional range of the optimum values of layer thicknesses, which provides a high diffraction efficiency in the operating wavelength range of 1.06 μm, is suggested. The stability of the diffraction efficiency with respect to random errors in the thickness of insulator layers deposited is investigated numerically. 相似文献
4.
K. C. Johnson 《Applied Physics A: Materials Science & Processing》1981,25(2):169-178
Coupled-wave theory is developed in full generality for unrestricted grating and polarization geometries. The analysis applies
to composite gratings modulated dielectrically, magnetically, and in absorptivity; and is also developed for gratings nonuniform
with depth. 相似文献
5.
基于对体光栅衍射效率的计算分析,本文直接地、精细地讨论了体光栅的功率守恒问题.结果指出:弱耦合前提假定下的双波耦合波二阶理论,不能严格地满足能量平衡准则. 相似文献
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基于严格耦合波理论建立了多层介质膜光栅的衍射机理模型,给出了TE波自准直条件下多层介质膜光栅衍射效率的表达式.以-1级衍射效率为评价函数,分析了表面浮雕结构分别为HfO2和SiO2材料的介质膜光栅获得衍射效率优于96%的结构参数.数值计算表明,顶层材料为HfO2的介质膜光栅具有更宽的结构选择范围.最后分析了介质膜光栅的制备容差和允许的入射角度范围.
关键词:
衍射效率
多层介质膜光栅
严格耦合波理论 相似文献
8.
A general method for analyzing the multilayer planar optical waveguide is presented. This method can also be used to predict the evolution of a wave propagating in the multibranch planar waveguide. The numerical simulation results show that the prediction is correct. 相似文献
9.
Hiroyuki Okamoto Kohei Noda Moritsugu Sakamoto Tomoyuki Sasaki Yasuhiro Wada Nobuhiro Kawatsuki Hiroshi Ono 《Optical Review》2017,24(4):510-516
We developed a method for the design of multilevel anisotropic diffraction gratings based on a genetic algorithm. The method is used to design the multilevel anisotropic diffraction gratings based on input data that represent the output from the required grating. The validity of the proposed method was evaluated by designing a multilevel anisotropic diffraction grating using the outputs from an orthogonal circular polarization grating. The design results corresponded to the orthogonal circular polarization grating structures that were used to provide outputs to act as the input data for the process. Comparison with existing design methods shows that the proposed method can reduce the number of human processes that are required to design multilevel anisotropic diffraction gratings. Additionally, the method will be able to design complex structures without any requirement for subsequent examination by a human designer. The method can contribute to the development of optical elements by designing multilevel anisotropic diffraction gratings. 相似文献
10.
A method of image deblurring is described, in which the restoration filter is derived from Ronchi rulings. Although two-dimensional spatial filtering is used, the method employs a line source, resulting in significant noise reduction. Experimental results are given. 相似文献
11.
Four alternative criteria for the occurence of Bragg regime diffraction by phase gratings are presented and evaluated. 相似文献
12.
多层膜闪耀光栅衍射的运动学研究 总被引:1,自引:0,他引:1
用 X射线运动学理论对软 X射线多层膜闪耀光栅的衍射特性进行了详细的研究 ,得到了衍射规律的一般表达式 ,讨论了产生衍射极大值的条件、光谱特性 ,不同于光栅和多层膜的色散特性。以及用作软 X射线单色器的一般性问题。发现只要选择合适的光栅参数 ,便可以将衍射光的大部分能量集中到某一个非零衍射级上。 相似文献
13.
A two-dimensional diffraction grating for phonons is described. It scatters thermal phonons strongly when their dominant wavelength is equal to the grating's lattice constant. Through measurements of the Kapitza resistance between the silicon crystal carrying the grating and liquid helium, it is shown that the scattering by the grating is predominantly coherent, as expected for phonon diffraction. 相似文献
14.
L. L. Doskolovich S. I. Kharitonov O. I. Petrova V. A. Soifer 《Optics and Lasers in Engineering》1998,29(4-5)
A method for the design of perfectly conducting varied-depth binary diffraction gratings is proposed. The design uses the rigorous modal expansion method and is based on the gradient search algorithm for optimization of grating structure from the condition of the generation of a desired array of diffraction orders. The designs of varied-depth binary gratings with equal order intensities are reported with an efficiency of more than 90% and root-mean square errors of 2–7%. 相似文献
15.
本文提出了测试平面衍射光栅的分辨特性的新方法,用干涉法测量光栅衍射的波阵面的相位,得出衍射波阵面的三维波面图,并用所取得的相位数据作傅里叶变换求得其在谱面上的光谱衍射斑——光谱线像的强度分布,并可据此确定半宽度值和分辨极限.文中叙述了这一新方法的优点、基本原理和实验方法,并给出应用这方法测量一批光栅所得结果中的两个例子,结果表明,与通常所用直接扫描光谱线法所测结果相符合. 相似文献
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R. Matull R. A. Rupp J. Hehmann K. Ibel 《Zeitschrift für Physik B Condensed Matter》1990,81(3):365-369
Cold neutrons are diffracted by thick phase gratings which have been produced by light-optical holography in poly-(methyl methacrylate) (PMMA). The neutron diffraction efficiency is investigated in the Laue case as a function of the angle of incidence by rocking the sample. The dynamical theory of neutron diffraction allows to relate the measured diffraction efficiency to the modulation amplitude of the neutron-optical refractive index. The absence of higher order diffraction peaks proves that this modulation is sinusoidal. Further experimental parameters are shown to influence the diffraction in accordance with the dynamical theory: the wavelength of neutrons, the sample thickness, and the grating period. Laser diffraction experiments allow us to give upper limits for the uniformity of the grating constant throughout the sample volume. The gratings show properties which are promising for the fabrication of high-precision control samples for cold and very cold neutron spectrometers, for the construction of neutron-optical instruments, and the possibility to measure photoinduced changes of neutron-optical potentials. 相似文献
18.
Nowadays in order to protect against the waves available in surrounding MRI rooms we use mu-metal. We suggest to use 1D dielectric gratings to protect MRI rooms from surrounding mobile waves. Hence, we present a grating with maximum reflection by RCWA method. 相似文献
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