共查询到17条相似文献,搜索用时 62 毫秒
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提出了一种基于六角格子光子晶体波导微腔和Fabry-Perot(FP)腔非对称耦合的全光二极管结构, 它由一个包含非线性Kerr介质的高Q值微腔与一个光子晶体波导中的FP腔组成. 通过有限时域差分方法对其传输特性进行了仿真, 发现通过两腔的非对称耦合可以实现在特定光强度下的正向传输、反向截止的功能. 在靠近微腔方向光入射时, 特定强度的光可以激发非线性微腔的Kerr效应, 改变了Fano腔的共振频率, 从而变成透射状态. 而远离微腔方向光入射, 由于这个不对称的结构造成场局域的分布不对称, 激发微腔Kerr效应的光强还不够, 所以光不能透射. 所设计的全光二极管结构具有良好的性能参数: 最大透射率高和高透射比、光强阈值低和易于集成等. 相似文献
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本文设计了一种双层开口方环和双C型结构的超材料结构,在太赫兹波段具有双波段的类电磁诱导透明效应.该结构在1.438 THz和1.699 THz处出现透射峰.通过电磁场分布分析讨论产生双频带电磁诱导透明的原因,利用等效电路分析方法进一步解释了超材料中的类电磁诱导透明效应.研究了超材料开口方环的开口大小和双C型结构距离以及改变入射角度时对透射窗口的影响,结果发现在改变入射角度时,所设计材料透射谱线变化较大,表现出对角度的高敏感性.同时,改变环境的介电常数可以得到该结构的透射谱产生明显的红移.以上研究结果表明该结构在角度滤波器,折射率传感器等器件中有潜在的应用. 相似文献
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光子带隙是指某一频率范围的波不能在周期变化的空间介质中传播,即这种结构本身存在“禁带”,并已成功地应用于滤波器、放大器和混频器等器件的设计中.此前,许多专家都致力于提高带隙的反射率,但其只能逐渐接近1.本文在囚禁于一维光晶格中的冷原子介质中实现两个可调光子带隙,并通过选择两基态为精细结构的三能级∧型原子系统,考虑自发辐射相干效应来探究这两个带隙的反射率.适当调节参数,探测场出现增益,从而获得较高反射率的带隙结构,甚至可以超过1.此外,两个带隙反射率还可以通过调节偶极矩之间的夹角以及非相干驱动场强度等参数来操控. 相似文献
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The bandgap effect of photonic crystals (PCs) and the effect of grating diffraction can be used to improve the extraction efficiency of light from the light-emitting diode (LED). The transmission of light at certain wavelength through periodic sub-wavelength hole arrays in metal films is extraordinary, surface plasmon (SP) effects effectively. In this letter, silver metallic photonic crystals with square lattice of cylinder unit cells are fabricated in GaN layer of GaN-based blue LED. We use the finite-difference time-domain (FDTD) method to investigate the optical transmission, the results show that the light extraction efficiency is enhanced by more than four times. Then we use the surface plasmon dispersion relation to analyze the mechanism of antireflection. 相似文献
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Optical control of light propagation in photonic crystal based on electromagnetically induced transparency 下载免费PDF全文
A kind of photonic crystal structure with modulation of the refractive index is investigated both experimentally and theoretically for exploiting electromagnetically induced transparency(EIT).The combination of EIT with periodically modulated refractive index medium gives rise to high efficiency reflection as well as forbidden transmission in a threelevel atomic system coupled by standing wave.We show an accurate theoretical simulation via transfer-matrix theory,automatically accounting for multilayer reflections,thus fully demonstrate the existence of photonic crystal structure in atomic vapor. 相似文献
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This paper describes the spatial transmission of electromagnetically induced transparency and four-wave mixing signals in the photonic bandgap structure, which are modulated using the adjustable parameters of light fields. The spatial transmission patterns of the relevant signals are experimentally investigated with respect to the optical nonlinear Kerr effect that occurs in the modulation process. The experimental results reveal the spatial transmission patterns of the probe transmission and the four-wave mixing signals, such as focusing, defocusing, shifting, and spatial splitting. This study explains how the tunable parameters of light fields and their interactions with each other can regulate the spatial transmission of the light fields by changing the refractive indices of media, which provides a new research perspective and a degree of experimental technology support for more efficient all-optical communications. 相似文献