Statistical analysis of subnanometer residual disorder in photonic crystal waveguides: Correlation between slow light properties and structural properties
Statistical analysis of subnanometer residual disorder in photonic crystal waveguides: Correlation between slow light properties and structural properties
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DOI：
10.1116/1.3622289
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发表时间：
2011-09-01
影响因子：
1.4
通讯作者：
Houdre, R.
中科院分区：
文献类型：
--
作者：
Le Thomas, N.;Diao, Z.;Houdre, R.
作者提出了一个统计研究的剩余无序在名义上相同的平面光子晶体波导工作在慢光制度。重点是所发挥的作用，由亚纳米尺度的剩余障碍固有的国家的最先进的电子束（EB）光刻系统，特别是，对影响的性质的剩余障碍上的最大值的导模群指数。作者分析的表面积，位置和形状的空气孔，定义的光子晶体与优化的扫描电子显微镜显微照片的统计特性。作者通过将这种结构无序的微观分析与基于傅立叶空间成像技术的大视场光学表征相关联，确定了孔面积波动是色散慢光制度退化的主要来源。具有最大群指数（n（g）= 40）的结构表现出低至0.4nm的孔半径的标准偏差σ。这种低的σ值已经显著限制了导模的最大可实现的群折射率，强调了残余无序对慢光机制的性能的剧烈影响。电子显微照片的均方分析揭示孔位置的标准偏差低于0.6nm的上限。这个上限来自于扫描电子显微镜本身的固有缺陷，这阻碍了量化的EB光刻系统引起的位置无序。作者已经确定孔的形状和孔位置的组指数之间没有相关性。因此，空穴面积波动是目前要控制的主要参数，以提高慢光区的性能。(C)2011年美国真空学会。[DOI：10.1116/1.3622289]
The authors present a statistical study of residual disorder in nominally identical planar photonic crystal waveguides operating in the slow light regime. The focus is on the role played by the subnanometer scaled residual disorder inherent to state-of-the-art electron-beam (EB) lithography systems, in particular, on the impact of the nature of the residual disorder on the maximum value of the guided mode group index. The authors analyze the statistical properties of the surface area, the position, and the shape of the air holes that define the photonic crystal with optimized scanning electron microscope micrographs. The authors identify the hole-area fluctuation as the main source of degradation of the dispersive slow light regime by correlating such a microscopic analysis of the structural disorder with large field-of-view optical characterizations based on a Fourier space imaging technique. The structure with the largest group index (n(g) = 40) exhibits a standard deviation sigma of the radius of the hole as low as 0.4 nm. Such a low value of sigma, which already significantly limits the maximum achievable group index of the guided mode, stresses the drastic impact of the residual disorder on the performances of the slow light regime. A mean square analysis of the electronic micrographs reveals that the standard deviation of the hole position is lower than an upper limit of 0.6 nm. This upper bound comes from the intrinsic imperfections of the scanning electronic microscope itself, which hinders to quantify the position disorder induced by the EB lithography system. The authors have identified no correlation between the shape of the holes and the group index as for the hole position. As a result, the hole-area fluctuation is currently the main parameter to control in order to improve the performance of the slow light regime. (C) 2011 American Vacuum Society. [DOI: 10.1116/1.3622289]