Determining the electromagnetic field response of photonic and plasmonic resonators is a formidable task in general. Field expansions in terms of quasi-normal modes (QNMs) are often used, since only a few of these modes are typically required for an accurate field description. We show that by exploiting the structure of Maxwell’s equations, conjugate-symmetric frequency-domain field expansions can be efficiently computed via a Lanczos-type algorithm. Dominant QNMs can be identified a posteriori with error control and without a priori mode selection. Discrete QNM approximations of resonating nanostructures are presented and the spontaneous decay rate of a quantum emitter is also considered.

中文翻译：

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光子和等离子体共振器的模态分析。

通常，确定光子和等离子体谐振器的电磁场响应是一项艰巨的任务。经常使用准标准模式（QNM）进行场扩展，因为对于精确的场描述通常仅需要这些模式中的少数几个。我们表明，通过利用麦克斯韦方程组的结构，可以通过Lanczos型算法有效地计算出共轭对称频域场扩展。主导QNMs可以被识别后验与误差控制和没有先验模式选择。提出了共振纳米结构的离散QNM近似，还考虑了量子发射器的自发衰减率。