The angular spectrum decomposition (ASD) is a powerful tool for analyzing the interaction between spherical particles and shaped beams, in which homogeneous plane waves and/or evanescent waves are expanded into series of vector spherical harmonics (VSH). The paper presents a numerical study on the VSH expansion of the evanescent wave and its behavior in the field reconstruction of the shaped beam. It is revealed that the beam shape coefficients (BSCs) of the evanescent waves increase exponentially along the increasing partial wave number, consequently extending the convergence of the series and restricting the field reconstruction into a limited space.

中文翻译：

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异形光束角谱分解中e逝波的球谐展开

角谱分解（ASD）是分析球形粒子与成形光束之间相互作用的有力工具，其中均匀的平面波和/或e逝波扩展为一系列矢量球谐（VSH）。本文对on逝波的VSH扩展及其在异形光束场重构中的行为进行了数值研究。揭示了van逝波的光束形状系数（BSCs）随增加的部分波数呈指数增长，从而扩展了序列的收敛性并将场重构限制在有限的空间中。