Ab initio computational analysis of spectral properties of dielectric spheroidal resonators interacting with a subwavelength nanoparticle
Ab initio computational analysis of spectral properties of dielectric spheroidal resonators interacting with a subwavelength nanoparticle
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DOI：
10.1103/physreve.99.013310
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发表时间：
2019-01-22
影响因子：
2.4
通讯作者：
Deych, Lev
中科院分区：
文献类型：
--
作者：
Shuvayev, Vladimir;Deych, Lev
提出了一种有效的数值方法来确定椭球耳廊模谐振器与纳米介电粒子相互作用时的光谱特性和场的空间分布。所开发的方法是基于将T矩阵形式应用于单谐振腔与纳米粒子场的偶极近似相结合。该方法通过计算谐振器-粒子系统的散射场，入射场的形式为TE或TM偏振的单个WGM模，模拟了锥形光纤的共振激发。我们的计算表明，即使谐振器的形状与理想球体有很小的偏差(小于0.1%)，球面近似也是无效的。他们还证实了以前发展的球谐振腔的解析共振近似对谐振器-粒子系统的光谱特性给出了合理的定性描述。然而，人们发现，对共振近似的修正是足够重要的，以至于可以考虑实际的名义上的球谐振器来准确地分析实验数据。
An efficient numerical method for determining the spectral characteristics and spatial distribution of the field of a spheroidal whispering-gallery-mode (WGM) resonator interacting with a dielectric nanoparticle is presented. The developed approach is based on a combination of T-matrix formalism applied to a single resonator with a dipole approximation for the field of the nanoparticle. The method is illustrated by computation of the scattered field of the resonator-particle system illuminated by an incident field in the form of a single WGM mode of TE or TM polarization mimicking the excitation of the resonances by a tapered fiber. Our calculations show that even a very small (less than 0.1%) deviation of the resonator's shape from an ideal sphere renders spherical approximation invalid. They also confirm that analytical resonant approximation for spheroidal resonators developed previously gives a reasonable qualitative description of the spectral characteristics of the resonator-particle system. It was found, however, that corrections to the resonant approximation are significant enough for realistic nominally spherical resonators to be taken into account for accurate analysis of the experimental data.