Critical field enhancement of asymptotic optical bound states in the continuum.
Critical field enhancement of asymptotic optical bound states in the continuum.
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DOI：
10.1038/srep18301
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发表时间：
2015-12-17
影响因子：
4.6
通讯作者：
Magnusson R
中科院分区：
文献类型：
--
作者：
Yoon JW;Song SH;Magnusson R
我们研究了亚波长周期硅薄膜中嵌入光子束束态的光谱奇异性和临界场增强因子。尽管存在深表面调制和结构的垂直不对称性，但在精确嵌入本征值的光谱附近获得了支持场增强因子大于108的超高Q共振。利用解析耦合模模型处理部分共振Q和场增强因子之间的关系，我们得到了在存在物质耗散的情况下最大化与这些光子束缚态相关的场增强的一般策略。场增强的解析表达式与严格的数值计算定量地一致。因此，我们的结果为在各种应用中基于光学束束态的实际谐振元件的设计提供了一般性的知识。
We study spectral singularities and critical field enhancement factors associated with embedded photonic bound states in subwavelength periodic Si films. Ultrahigh-Q resonances supporting field enhancement factor exceeding 108 are obtained in the spectral vicinity of exact embedded eigenvalues in spite of deep surface modulation and vertical asymmetry of the given structure. Treating relations between the partial resonance Q and field enhancement factors with an analytical coupled-mode model, we derive a general strategy to maximize the field enhancement associated with these photonic bound states in the presence of material dissipation. The analytical expression for the field enhancement quantitatively agrees with rigorous numerical calculations. Therefore, our results provide a general knowledge for designing practical resonance elements based on optical bound states in the continuum in various applications.