Abstract: The authors theoretically studied the propagation properties of surface plasmon polaritons (SPP) in cylindrical gold nanowires at the wavelength of 632.8nm. By solving the Maxwell's equations, the propagation constant of the SPP modes and the propagation properties of the modes are obtained, including their propagation lengths and effective radiuses. The authors find the change of the modes' properties influenced by the structure of the waveguides and the dielectric, which is a trade-off between the modes?propagation length and effective radiuses. Through calculation, the authors find out good propagation properties of the surface plasmon modes under certain dimension. When both the radius of the gold core and the thickness of the SiO₂ layer is 40 nm, HE₁₁ mode can travel for 103. 6 μm, with an effective radius of only 642 nm.

Key words: cylinderical gold nanowire, surface plasmon, propagation length, effective radius

摘要： 从理论上研究了圆柱形金纳米线中, 可见光波长下(λ= 632. 8 nm) 表面等离激元模式的传输性质。通过求解麦克斯韦方程组, 得到圆柱形金纳米线中表面等离激元波导的传播常数, 进而得到表面等离激元模式的传输性质, 包括其传播长度及有效半径等。还发现了表面等离激元模式的传输性质受到模式结构以及介质介电常数的影响, 并且得到了表面等离激元传输距离和能量局域之间的普遍矛盾, 即能量局域越好传播距离越短。通过计算, 能够在特定的结构参数下获得较好的局域特性和传播长度, 例如, 当金属芯半径为 40 nm, 介质( SiO₂ ) 厚度为 40 nm时, HE₁₁ 模式的传播长度为 103. 6 μm, 有效半径 642nm。

关键词: 圆柱形金纳米线, 表面等离激元, 传播距离, 有效半径