共查询到18条相似文献,搜索用时 156 毫秒
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运用严格耦合波理论对亚波长光栅的模场分布进行讨论,通过位相匹配方程建立衍射级、光栅矢量和波导传输常数的关系,得到波导光栅实现偏振分束功能时对应的设计参数;针对布拉格反射层良好的反射特性,设计了一种亚波长偏振分束器。为了提高光栅的耦合效率,在基底增加Bragg反射层,将传统偏振分束器的透射光反射,与输入光相干叠加,满足相位匹配条件后耦合输出,使耦合效率大大增加。 相似文献
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采用严格耦合波理论并结合矩阵LU分解法,分析了亚波长介质光栅的刻槽深度、占空比、入射角、入射波长等参数对TE偏振和TM偏振0级衍射效率的影响。结果表明:在1 550 nm波长处,出现瑞利反常现象。由此提出利用瑞利反常现象设计工作波长为1 550 nm的偏振分束光栅,通过优化设计确定了最佳设计参数,即光栅周期为l0/2,瑞利入射角为30°,刻槽深为0.9l0,占空比为0.5。结果表明,参数优化后的偏振分束光栅可以使TE偏振0级反射波和TM偏振0级透射波同时达到近100%的衍射效率。 相似文献
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基于严格耦合波理论分析了一种非对称偏振分束光栅的设计。这种偏振分束光栅分别在1级和0级衍射级次上衍射TE和TM偏振波。介绍了利用遗传算法设计偏振分束光栅的方法,并给出了优化实例。仿真结果表明:在设计波长为1.55时,TE偏振波在1级的衍射效率大于93%,TM偏振波在0级的衍射效率大于99%,此时1级和0级的透射消光比分别达到了9914.1和46841.5。通过对设计结果的分析发现,该偏振分束光栅在设计波长附近100nm的波长范围内都具有较高的消光比(大于100),达到了较好的偏振分束效果。 相似文献
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综合等效介质理论和表面等离子激元(SPP)Bloch模型,对比分析了两种新的亚波长光栅结构:二维矩形金属光栅和二维椭圆柱金属光栅。利用时域有限差分(FDTD)算法,对比分析了两种结构的透射率及其相位延迟与入射光波长及偏振角变化的关系,尤其两种结构实现λ/4波片功能所对应的透射特性。仿真结果表明,当入射光偏振角为75°时,两种结构均可实现λ/4波片功能,此时二维矩形和椭圆柱金属光栅的透射率分别为0.77和0.67,表明二维矩形金属光栅比椭圆柱光栅具有更好的透射效果。对应550~800nm的入射波长,两种光栅在各自允许的入射偏振角范围内均表现了较为平坦的宽带透射特性。 相似文献
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针对传统偏振分束器窄波段、窄角度范围的不足,研制了一种在宽波段宽角度范围内具有180°分光功能的偏振分束器/耦合器。该器件基于线栅偏振器和亚波长光栅结构原理设计,利用半导体工艺的刻蚀技术制作。利用一维金属线栅对入射电磁波的偏振响应和亚波长光栅仅存在零级衍射的特性,实现了较宽的通带宽度与可接受角度范围、极大的分光角度、高消光比和低插入损耗。实验测得透射、反射消光比均大于20 dB,插入损耗小于0.5dB。通过自行搭建的微结构测试平台,测量了p、s光的透射率、反射率随入射角度变化的曲线,和严格耦合波理论模拟结果符合。深入分析了制作中的过刻蚀对性能产生的影响。 相似文献
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为了能够实现垂直腔面发射激光器(VCSEL)偏振无关特性,提出了将偏振无关光栅与half-VCSEL集成的方法。基于严格耦合波法,分析了光栅参数对偏振无关二维光栅反射特性的影响,经过模拟计算,发现在光栅周期为691~719 nm、光栅宽度为408.73~467.60 nm时,偏振无关二维光栅有210 nm的高反射带宽。将偏振无关二维光栅与中心波长为1.55μm的half-VCSEL进行集成,得到了中心波长为1.55μm的偏振无关波长可调谐VCSEL,经过光学传输矩阵计算,可得该偏振无关波长可调谐VCSEL的波长调谐范围可达93 nm。 相似文献
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利用二维结构薄膜构建了具有偏振选择特性的新型相位光栅,借助严格耦合波分析(RCWA)方法计算了光栅各级衍射强度随入射光波长及入射角的变化,发现在垂直入射情况下,波长600—640 nm范围内,相位光栅对横向电学(TE)模主要产生0级衍射,而对横向磁学(TM)模产生±1级衍射,在波长633nm处,0级衍射光的偏振消光比为109.8,±1级衍射光的偏振消光比为334.6.利用时域有限差分方法对这种相位光栅的偏振分束现象进行了模拟,偏振分离角在玻璃基板内可以达到10°左右,最后模拟了入射角为23°时光栅对不同偏 相似文献
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A Si–ZnS double-layer subwavelength grating is theoretically used as a high-efficient polarizing beam splitter. To design this structure, the rigorous coupled-wave analysis (RCWA) is applied to study the reflectivity and transmissivity for the TE and TM polarization, respectively. Simulation results show that both the zero-order reflection for TE polarization and the zero-order transmission for TM polarization can exceed 90% in a wide tunable working incident angle range from 48° to 72°. Moreover, the proposed polarizing beam splitter has a working wavelength that is in the range of 1500–1600 nm. 相似文献
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Optimal design of sub-wavelength metal rectangular gratings for polarizing beam splitter based on effective medium theory 下载免费PDF全文
A novel optimal design of sub-wavelength metal rectangular
gratings for the polarizing beam splitter (PBS) is proposed. The
method is based on effective medium theory and the method of
designing single layer antireflection coating. The polarization
performance of PBS is discussed by rigorous couple-wave analysis
(RCWA) method at a wavelength of 1550~nm. The result shows that
sub-wavelength metal rectangular grating is characterized by a high
reflectivity, like metal films for TE polarization, and high
transmissivity, like dielectric films for TM polarization. The
optimal design accords well with the results simulated by RCWA
method. 相似文献
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It is desirable to obtain high efficiency with polarization-independence and wideband properties for incident wavelength. A metal-mirror-based grating is presented to diffract the incident wave into reflection orders with high efficiency for TE and TM polarization. The modal method and rigorous coupled-wave analysis (RCWA) are used together to optimize a metal-mirror-based grating effectively. From the analysis of the modal method, it is feasible to realize such a grating with the prescribed grating duty cycle and period. Accurate parameters of the grating depth and thickness of the connecting layer are optimized using RCWA. Compared with the reported binary simple grating, high efficiency can be improved greatly for the incident wavelength of 1550 nm in dense wavelength division multiplexing. The diffraction investigation indicates that a wideband property for incident wavelength can be obtained for such a novel metal-mirror-based grating. 相似文献
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D. Zhang P. Wang X. Jiao C. Min G. Yuan Y. Deng H. Ming L. Zhang W. Liu 《Applied physics. B, Lasers and optics》2006,85(1):139-143
Optical polarization properties of aluminum, gold and aluminum/gold subwavelength metallic gratings (SWMGs) are investigated numerically in the visible light band. Their performance as polarizing beam splitters are simulated with RCWA for varied metallic materials, grating depth and incident angle. Metallic waveguide theory is applied to explain the performance difference between Au and Al grating. A new type of Al/Au bimetallic is also investigated numerically for potential applications. PACS 42.79.Dj; 42.81.Gs; 73.20.Mf 相似文献
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亚波长介质光栅的闪耀特性分析 总被引:1,自引:1,他引:0
采用严格耦合波理论与矩阵LU分解法,求解了亚波长矩形介质光栅的衍射场,给出了TE和TM偏振波的耦合波方程组及其矩阵形式.通过数值计算分析了TE和TM偏振波的入射角、刻槽深度、入射波长等参量对+1级衍射波衍射效率的影响.结果表明,当Λ=0.5λ0,θ=55°,d=0.38λ0,λ=10.6 μm时可以实现对TE偏振波+1级的闪耀,衍射效率达到近90%,同时具有较宽广的角度适应范围. 相似文献
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Shigeto Omori 《Optical Review》2001,8(4):254-259
A data projector using three liquid crystal display panels has a complex optical system. The illuminating optics separate the beam from a light source into three primary colors and separate those into opposite polarizations using multi-layer films and prisms. A reflection grating with the period of subwavelength has high diffraction efficiency for p polarized light and high regularly reflectance for s polarized light. The diffraction angle of a grating largely depends on the wavelength, because a diffractive optical element (DOE) has large chromatic dispersion. The grating with the period of subwavelength can separate the unpolarized light into polarization components effectively using its polarization dependency and can separate white light into color components using its chromatic dispersion simultaneously. The grating makes the optical system simpler and smaller than those with conventional devices. In this paper the efficiency of polarization separation for the grating is calculated by a rigorous analytical method. Next, the condition for color separation is calculated by Snell#x0027;s law, and an optical system using a grating that performs polarization and color separation is proposed. Experimental results of the DOE fabricated are well matched with those of this simulation. 相似文献
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Modal analysis of a deep-etched low-contrast two-port beam splitter grating under Littrow mounting is presented. The guideline for the design of a subwavelength transmission fused-silica phase grating as high-efficiency grating, polarizing beam splitter (PBS), and two-port beam splitter, is summarized. As an example, a polarization-independent two-port beam splitter grating is designed at wavelength of 1064 nm. We firstly analyzed the physical essence of the grating by the simplified modal method. The guideline for the grating design and the approximate grating parameters are obtained. Then using the rigorous coupled-wave analysis (RCWA) with parameters varying around the approximate ones, optimum grating parameters can be determined. With the design guideline, the time for the rigorous calculation of the grating profile parameters can be reduced significantly. 相似文献