Abstract

Excitation and focusing of a radially convergent surface plasmonic wave on the free surface of a gold film in the Kretschmann geometry have been considered based on the theory of reflection of a plane electromagnetic wave from a plane-layered structure. The electric-field distribution in the vicinity of the focus on the free film surface has been quantitatively investigated. Based on this distribution and the theory of thermally-assisted field electron emission from a metal, the time-averaged electron-emission current has been estimated in dependence of the amplitude of the normal component of the wave electric field at the focal-distribution center. It is shown that the major part of the emission current originates in the region near the focal center with a diameter of about a tenth of the operating wavelength in vacuum; the emission current originating from the diffraction rings around the central maximum is negligible.

中文翻译：

---

在金属膜的自由表面上对称会聚的表面等离子体波的焦点区域的电子发射

摘要

基于基于平面分层结构的平面电磁波的反射理论，已经考虑了以Kretschmann几何形状在金膜的自由表面上径向会聚的表面等离子体激元的激发和聚焦。已经定量研究了在自由膜表面上焦点附近的电场分布。基于这种分布和从金属进行的热辅助场电子发射的理论，已根据焦点分布中心处波电场的法向分量的振幅估算了时间平均的电子发射电流。结果表明，发射电流的主要部分起源于焦点中心附近的区域，其直径约为真空中工作波长的十分之一。