Surface plasmon polaritons can be efficiently excited using attenuated total internal reflection techniques or with diffraction gratings. An alternative way actively studied in recent years is the use of nanoantennas. Here, we show that the amplitude of surface plasmon polariton excited by a nanoantenna can be found analytically using a well-known method for calculation of guided-mode amplitudes in the presence of current sources, which is widely used in the waveguide theory. The calculations are carried out for the simplest 2D case of an infinitely long cylindrical rod of a small radius illuminated by a plane wave and placed in the vicinity of metal substrate parallel to its interface. The validity of the analytical solution is confirmed by the results of numerical simulations.

可以使用衰减全内反射技术或衍射光栅有效激发表面等离激元极化子。近年来积极研究的另一种方法是使用纳米天线。在这里，我们表明，可以使用众所周知的方法在存在电流源的情况下使用计算导模振幅的众所周知的方法来分析地找到由纳米天线激发的表面等离子体激元极化的振幅，该方法在波导理论中得到了广泛使用。对于最简单的2D情况进行计算，该情况是无限小长圆柱杆，其半径较小，并被平面波照射，并放置在平行于其界面的金属基板附近。数值模拟结果证实了解析解的有效性。