共查询到20条相似文献,搜索用时 200 毫秒
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矩形槽光栅矢量模式理论的数值计算 总被引:1,自引:1,他引:0
本文根据矩形槽光栅的矢量模式理论进行了数值计算。对于任意入射方向及任意偏振态的入射场,计算了其衍射效率和偏振特性变化,并详细研究了光栅结构参数(周期、槽宽、槽深等)对衍射场的影响。 相似文献
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对称型闪耀光栅的矢量模态理论 总被引:6,自引:5,他引:1
本文将满足均匀矢量亥姆霍兹方程的标准矢量波函数作为基矢对对称型闪耀光栅槽内、外的电磁场分别进行矢量模式和矢量平面波展开。然后通过在槽内外分界面上的场耦合条件得到一组振幅系数方程组。从方程组中求解出相应的振幅系数,就可研究光栅的衍射场分布。该方法适用于对称型闪耀光栅对任意入射方向、任意偏振态入射场衍射问题的研究。在K_2=0入射情况下,其振幅方程组与已发表的文献[6]相同。 相似文献
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本文采用麦克斯韦(Maxwell)方程微分积分方程对波长尺寸的梯形反射光栅在TE模式(横向电场)偏振状态入射下,进行严格理论的计算和分析.表面电场计算表明,光栅刻槽斜边边界对于金属材料金和铝光栅表面电场分布具有明显效应,对于入射波长为λ=1.0μm附近的红外区域,金材料具有强烈的金属特性,此时表面电场的斜边边界效应更加明显.表面电场及其远场衍射效率伴随刻槽深度变化,而振荡特性进一步阐明了此效应对近,远场的作用.该方程适用于任意形状光栅或单一散射体对任意入射方向,任意偏振态的衍射和散射问题. 相似文献
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采用了Hansen矢量波函数理论研究半圆形金属光栅的衍射效率问题,该方法适用于任意入射方向,任意偏振态入射场衍射问题的研究,结果表明,当入射光为p或s型偏振光时,其结果与文献(1)的结果相同。 相似文献
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使用衍射光栅的分色分光方式一般以平行光入射情况为讨论基础,对于非平行光入射的情况讨论较少.本文基于菲涅尔衍射理论和角谱理论,将球面波与平面波的衍射波场联系起来,从而在传播函数中引入角度参量,结合分数泰伯效应的理论基础,推导出双波长宽角度入射光线经相位光栅衍射后的波场分布函数,并对推导出的函数进行数值模拟,得到像面不同位置衍射波场分布.与平行光入射时的标准波场分布相比较,得到宽角度入射时的衍射波场的横向展宽量和偏移量.通过调节光栅台阶的宽度,改变衍射场的展宽和偏移,使各个单一波长的衍射波场宽度小于光栅周期的一半,从而减少双波长光衍射波场的混叠.同时本文给出波场宽度与光栅台阶宽度的变化关系,选取光栅面上多个位置作为台阶宽度的计算点,并对整个光栅的台阶宽度进行曲线拟合,得到可以使双波长宽角度入射光实现良好空间分离的光栅参量.该结果可用于各类宽角度入射光线的光谱分离场合,如双波长成像、液晶显示和液晶投影等. 相似文献
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矩形槽光栅的矢量模式理论 总被引:8,自引:7,他引:1
本文引进满足均匀矢量Helmholtz方程的矢量波函数作为基矢,对矩形槽光栅的槽内和槽外的光场分别进行矢量平面波展开和矢量模式展开,并由耦合条件导出了求解展开系数的方程组,可进行数值计算.该方法可研究入射场的方向和偏振任意时的衍射效率、偏振特性变化等问题.在p偏振和s偏振的特殊情况下所得到的公式与用标量模式理论得到的结果一致. 相似文献
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A. A. Spikhal'skii 《Optics & Laser Technology》1989,21(6):395-399
The diffraction efficiency of smooth weak gratings can depend significantly on the profile of the gratings as, in the diffraction process there exists wave coupling. By adjusting the grating profile it is possible to obtain enhancement or suppression of the diffraction efficiency. Possible applications include improvements in grating devices, grating profile reconstruction, and precise control of the slightest periodical disturbances. Some numerical examples are given. 相似文献
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对称面形光栅TE模的衍射特性 总被引:3,自引:1,他引:2
本文采用耦合波方法计算了对称面形光栅的衍射效率,分析了光栅截面面形为正弦、三角形、矩形、梯形光栅衍射效率与光栅周期、沟槽深度的关系,计算了光栅的峰值衍射效率。理论计算表明:合理地选择光栅周期、沟槽深度,对称面形光栅都可以达到很高衍射效率,接近100%;光栅的峰值衍射效率基本出现在Bragg衍射且光栅的周期等于衍射波长时。 相似文献
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紫外刻划光栅母版及二代版衍射特性的模拟与分析 总被引:2,自引:0,他引:2
运用微分理论对刻线密度为1200 lp/mm的紫外刻划光栅母版及其二代复制版的衍射特性做了模拟,指出了二者之间存在的差异,并与测试结果做了对照。数值模拟表明,紫外刻划光栅二代复制版的衍射特性与其母版略有不同,原因是光栅槽形发生了改变,分别给出了采用多项式拟合槽形函数和傅里叶级数拟合槽形函数的方法。此理论分析方法为澄清光栅复制工艺中的争议完善翻版技术以及寻找提高紫外光栅衍射效率的途径提供了很好的理论参考依据。 相似文献
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A method to design lasers that emit an arbitrary beam profile is studied. In these lasers, output-coupling is performed by a diffraction grating that imposes a phase and amplitude distribution onto the diffracted light. A solid-state laser emitting beams with a two-dimensional Airy intensity profile is demonstrated both theoretically and experimentally. In this case, the diffraction grating adds a transverse cubic phase to the diffracted light. An Airy beam is obtained by performing optical Fourier transform of the out-coupled light. The laser beam profile and power characteristics are shown to agree with theory. 相似文献
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A newly designed grating used in terahertz region is proposed, which is composed of the trapezoidal elements repeated successively along one dimension of the substrate, and uniform interval(the grating period) repeated along the other dimension. The transmission of the grating owns a designable trapezoidal profile dependent on the geometric dimensions of the element. The far-field diffraction patterns of a designed grating at incident broadband terahertz frequencies, with element dimensions of upper, lower side and period of 50, 250, and 300 μm, respectively, are simulated by the scalar diffraction theory. The simulation results indicate that the terahertz grating exhibits a property of single-order diffraction,and the diffraction efficiency of the first order reaches 6.6%, exceeding that of a traditional sinusoidal amplitude grating with identical period and duty cycle. Owing to the regular architecture and the high single-order diffraction efficiency, the grating is easy to fabricate and shows great potential applications in single-shot spectral measurements of weak broadband terahertz pulse. 相似文献
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An analytical model of the diffraction energy exchange between the radiative and the waveguide modes in a planar optical waveguide corrugated by a waveguide grating with an arbitrary form of teeth is developed on the basis of the coupled-wave method. It is shown that the mechanism of the energy exchange between the modes is determined by the partial interaction of all components of the spatial frequency spectrum of the waveguide modes with the corresponding components of the spatial frequency spectrum of the grating. It is established that gratings with an asymmetric tooth profile providing a shift of the peak of the spatial frequency spectrum toward matching are characterized by a higher diffraction efficiency α; however, at small thicknesses δ of the waveguide grating, the efficiency is almost independent of the tooth profile. It is shown that gratings with a symmetric profile give on average a decreasing dependence α(δ), while gratings with an optimized asymmetric profile yield a monotonically increasing saturating dependence α(δ). 相似文献
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A binary phase grating capable of shaping an incident Gaussian beam to a flattop beam in a Fourier domain is designed iteratively. It is essential in grating design to consider the phases of diffracted waves by the grating, in addition to their amplitude uniformity and diffraction efficiency. The optimized grating phase produces the in-phase diffracted waves that interfere constructively to form a uniform amplitude and phase profile. The dependence of the shaped profile on the illuminating amplitude distribution, the grating misalignment, and the lens focusing error is investigated by computer simulation and optical experiment. 相似文献