共查询到19条相似文献,搜索用时 109 毫秒
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利用传输矩阵法数值计算了一维全息光子晶体的带隙结构,分析了针对记录材料重铬酸盐明胶(DCG),折射率周期性渐变的一维全息光子晶体结构的透射谱特性.通过计算记录光路中相干光束以不同入射角干涉时产生不同的禁带分布范围,与改变再现光路中光束和干板的夹角相比较,提出了弥补固定厚度DCG产生光子晶体的禁带分布范围较窄的方法. 相似文献
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激光全息法制作二、三维光子晶体相比于传统半导体微加工及精密机械加工技术具有很多优势,比如通过一次光辐射就可以制作出大体积、均匀的周期性结构,且能更自由、更容易地控制光子晶体结构.提出一种多光束干涉模型,通过设计模型中光束的各项参数,计算分析出二、三维光子晶体的结构.基于平面波展开法,理论计算了fcc结构光子晶体的完全禁带随填充率和介电常数比变化的情况.以上计算结果为后期实验中采用激光全息法制作二、三维光子晶体结构提供了良好的指导方向和理论依据.
关键词:
光子晶体
激光全息
多光束干涉
完全禁带 相似文献
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利用表面光子晶体能大幅提高发光二极管(LED)的外量子效率, 但如何制备大面积的纳米光子晶体是该研究方向的主要难点之一. 本文基于纳米压印技术在氮化镓基发光二极管(GaN-LED)表面制作孔状二维光子晶体. 通过以金属和聚合物双层掩膜干法刻蚀法, 得到了很好的光子晶体图形转移效果. 最终在LED的p-GaN层表面获得了大面积光子晶体, 周期为450 nm, 纳米孔直径为240 nm. 器件测试结果显示, 有表面光子晶体的LED比没有光子晶体的LED, 光致发光强度峰值提高到了7.2倍. 相似文献
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一种新型红敏光致聚合物全息特性研究 总被引:1,自引:0,他引:1
对一种新合成的红敏光致聚合物进行了一系列研究 ,实验表明用该材料制作的全息干板获得了近 70 %的实时衍射效率 ,从理论上解释了曝光量与衍射效率的关系曲线 ,并研究了该材料的其它特性。这些结果表明 ,该红敏光致聚合物材料具有较好的实时全息记录特性。 相似文献
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采用一次性曝光光路制备了基于全息聚合物分散液晶的亚微米周期染料掺杂二维光子晶体,晶格常数为582nm.选取4-(二氰亚甲基)-2-甲基-6-(4-二甲氨基苯乙烯基)-4H-吡喃作为激光染料,利用输出波长为532nm的Nd:YAG倍频脉冲激光器作为抽运光源对染料掺杂二维光子晶体进行抽运,得到了中心波长为627.4nm的窄线宽、低阈值的输出激光,激光线宽为0.4nm,阈值能量约为22.7 μJ.与目前国外的报道相比,激光线宽和阈值能量都有了很大幅度的降低.将其与基于一维光栅的分布反馈式激光器相比,线宽从1.4
关键词:
全息聚合物分散液晶
二维光子晶体激光器
带隙结构
阈值能量 相似文献
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用实验方法研究了一种新合成的绿光敏感光致聚合物的高密度全息存储性质.结果表明该种光致聚合物具有较高的衍射效率、大的动态范围和折射率调制度,适合做高密度数字全息存储的记录材料,但材料的灵敏度需要提高,同时读出过程必须考虑曝光过程所导致的布拉格偏移;利用角度复用技术在样品的同一位置记录了20个数字化数据信息页,存储密度达到0.125GBcm3,平均误码率达到5.15×10
关键词:
光致聚合物
高密度数字全息存储
布拉格偏移 相似文献
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Y. J. Liu H. T. Dai E. S. P. Leong J. H. Teng X. W. Sun 《Applied physics. B, Lasers and optics》2011,104(3):659-663
Electrically switchable two-dimensional photonic crystals were demonstrated using polymer-dispersed liquid crystal materials
based on the Talbot self-imaging effect of a single photomask. With the photomask subjected to a collimated Ar+ laser beam operating at 488 nm, a three-dimensional spatial light intensity pattern was created due to the Talbot self-imaging
effect. The spatial light intensity pattern was then recorded inside a cell filled with the liquid crystal/prepolymer mixture
to create photonic crystal structures. The surface morphology of the photonic crystals was examined by an atomic force microscopy.
It showed square structures with a lattice constant of ∼0.9 μm. The diffraction and electro-optical properties were also presented.
This approach shows a simple and fast fabrication. 相似文献
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Debashis Chanda Ladan E. Abolghasemi Peter R. Herman 《Applied Physics A: Materials Science & Processing》2008,93(1):33-37
Phase tunable multi-level diffractive optical elements define an attractive approach for single laser exposure fabrication
of 3-dimensional photonic crystal microstructures. The significant advantage of these multi-level diffractive optical elements
over two-level diffractive optical elements is the flexibility of fabricating a wide range of 3-dimensional periodic structures
by manipulating the relative phase of different diffracted beams. Here, phase tuning was applied to demonstrate fabrication
of a hybrid 3-dimensional structure intermediate between previously reported diamond-like Woodpile-type structure of tetragonal
symmetry and structure having body-centered-tetragonal lattice symmetry. Circularly polarized light was applied for the first
time to balance the diffraction order efficiencies and improve the structural uniformity. Design guidelines are presented
for generating diamond-like photonic crystal template that possesses complete photonic bandgap when inverted with high refractive
index materials. 相似文献
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R. Kruszka M. Ekielski K. Gołaszewska K. Korwin-Mikke Z. Sidor M. Wzorek D. Pierścińska R. Sarzała T. Czyszanowski A. Piotrowska 《Opto-Electronics Review》2011,19(1):51-55
The results of modelling of the influence of photonic crystal on the performance of VCSEL-type semiconductor laser structure
are shown and indicate that the use of those structures would significantly improve the working parameters of the devices.
The method of fabrication of photonic crystals in the Bragg mirrors of GaAs/AlGaAs-based VCSELs is presented. 相似文献
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Fabrication of Two-Dimensional Photonic Crystals with Controlled Defects by Combination of Holographic Lithography and Two-Photon Polymerization 下载免费PDF全文
A new ternary photopolymer system is used in fabricating photonic crystals (PhCs) with controlled defects by combination of single-photon and two-photon photopolymerization. The former process can produce PhCs in one-step recording with a low-power (tens mW) continuous-wave laser at 532nm, while the latter can create desired defects. The preparation of the material, the optical setup and the preliminary experimental results are given. Compared with other methods, this approach is much more accessible and convenient for use of visible light and has advantages of making PhCs in a large scale quickly and economicaJly and introducing any defects exactly, especially for three-dimensional structures. 相似文献
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研究了一种新型的对红光和蓝光敏感的非水溶性光致聚合物材料的全息存储特性。该聚合材料由复合单体、复合光敏剂、复合引发剂、链转移剂及成膜物等成分组成,它具有防潮、后处理简单、分辨率高及耐高温等特点,对红、蓝光2种衍射效率均不低于75%,灵敏度为(45~65)mJ/cm2。对该材料先后进行了双波长复用存储实验和角度复用存储实验,当用红光或蓝光再现时再现图像清晰可见,相邻2副图像之间无明显干扰,说明该材料具有良好的存储性能,适合作高密度数字全息存储的记录材料,可用作光通信中的波分复用器及其他光学元件。 相似文献
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S.N. Tandon M. Solja
i G.S. Petrich J.D. Joannopoulos L.A. Kolodziejski 《Photonics and Nanostructures》2005,3(1):10-18
The “superprism effect” is an effect observed in photonic crystal structures whereby the direction of light propagation is extremely sensitive to the wavelength and angle of incidence. To realize the superprism effect, new structures are presented which rely on the sensitivity of the phase velocity in a two-dimensional (2D) photonic crystal slab to observe angular magnification outside the photonic crystal medium. Constant frequency contour calculations for a photonic crystal slab of finite thickness are used to predict the phase velocity superprism effect. Further analysis using 2D finite-difference time-domain simulations indicate that a large area photonic crystal and wide excitation beam are necessary for clear observation of the superprism effect. A fabrication technique is demonstrated to achieve the structure's required nanometer-sized features over centimeter-scale areas. 相似文献
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Axisymmetric photonic crystal structures may be designed to possess interesting optical properties, particularly when the photonic band structure of the material is highly anisotropic. We use finite element calculations to demonstrate an approximate electromagnetic cloaking effect imparted by a structure consisting of concentric silicon photonic crystal layers. The results show that it is possible to bend light around an object by simply using anisotropy. The calculations show that the cloaking mechanism is fundamentally different from Pendry's approach. This design may work as a practical solution for optical cloaking. 相似文献