Plasmonic resonances of slender nanometallic rings
Plasmonic resonances of slender nanometallic rings
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DOI：
10.1103/physrevb.105.125412
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发表时间：
2022-03-14
影响因子：
3.7
通讯作者：
Schnitzer, Ory
中科院分区：
文献类型：
--
作者：
Ruiz, Matias;Schnitzer, Ory
我们发展了一个近似的准静态理论，描述了细长的纳米金属环及其构型的低频等离子体共振。首先，我们利用渐近变元将控制给定环结构的几何(与材料和频率无关)模的等离子体本征值问题归结为一维周期积分-微分问题，其中本征函数由与每个环相关的方位向电压和极化电荷分布表示。其次，我们得到了方位不变环(包括环面形状的环，但也考虑非圆形截面形状)以及此类环的同轴二聚体和链的约化本征值问题的闭合解。对于更一般的几何，包括方位不均匀环和非同轴结构，我们使用基于约化特征函数的傅里叶展开的半解析格式来求解约化本征值问题。第三，我们结合等离子体共振的准静态谱理论，研究和解释了多种纳米金属细环结构在平面波照射下的频率响应。
We develop an approximate quasistatic theory describing the low-frequency plasmonic resonances of slender nanometallic rings and configurations thereof. First, we use asymptotic arguments to reduce the plasmonic eigenvalue problem governing the geometric (material-and frequency-independent) modes of a given ring structure to a one-dimensional periodic integrodifferential problem in which the eigenfunctions are represented by azimuthal voltage and polarization-charge profiles associated with each ring. Second, we obtain closed-form solutions to the reduced eigenvalue problem for azimuthally invariant rings (including torus-shaped rings but also allowing for noncircular cross-sectional shapes), as well as coaxial dimers and chains of such rings. For more general geometries, involving azimuthally nonuniform rings and noncoaxial structures, we solve the reduced eigenvalue problem using a semianalytical scheme based on Fourier expansions of the reduced eigenfunctions. Third, we used the asymptotically approximated modes, in conjunction with the quasistatic spectral theory of plasmonic resonance, to study and interpret the frequency response of a wide range of nanometallic slender-ring structures under plane-wave illumination.