Optimized enhancement of electric field in a metallic hollow cylinder
Optimized enhancement of electric field in a metallic hollow cylinder
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金属空心圆柱体内电场的优化增强
DOI：
10.1088/1361-6463/ac04e6
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
R. Saito
中科院分区：
文献类型：
--
作者：
Y. Tian;M. S. Ukhtary;R. Saito
在金属空心柱体中，电场的增强随入射光的角频率而优化。激发方位角表面等离子体（SP）会产生共振增强，且增强在柱体内部均匀，这对光谱学有帮助。通过求解以圆柱体内外半径为函数的亥姆霍兹方程对电场的增强进行了数值计算，并对结果进行拟合，得到了电场增强的经验公式。最大增强发生在SP的谐振条件附近，但并不完全发生在SP的谐振频率处。计算的内外表面诱导电荷密度表明，最大增强发生在外表面诱导电荷密度最小的时候。我们认为圆柱外边界电荷密度的这种抑制是圆柱SP的两种本征模的线性组合的结果。
The enhancement of the electric field in a hollow metallic cylinder is optimized as a function of the angular frequency of incident light. A resonant enhancement occurs by exciting azimuthal surface plasmon (SP) and the enhancement is uniform inside the cylinder which is useful for spectroscopy. The enhancement of the electric field is numerically calculated by solving the Helmholtz equation as a function of the inner and outer radii of the cylinder from which an empirical formula for the enhancement is obtained by fitting the numerical results. The maximum enhancement occurs near the resonant condition of the SP but it is not exactly at the resonant frequency of the SP. The calculated induced charge density at the inner and outer surfaces show that the maximum enhancement occurs when the induced charge density at the outer surface becomes minimum. We suggest that such suppression of charge density at the outer boundary of the cylinder is the result of the linear combination of two intrinsic modes of the cylindrical SP.