Interaction of an ultrashort optical pulse with a metallic nanotip: A Green dyadic approach

摘要

We consider the interaction of an ultrashort optical pulse with a metallic nanotip. In the framework of the Green dyadic method, we calculate the time-dependent electric field in the vicinity of the metallic nano-object. The electric field enhancement at the tip apex, its temporal evolution, and its dependence upon the polarization of the incident electric field are addressed. By comparing the case of tungsten and gold nanotips, we show that significantly larger electric field enhancements can be obtained with the latter and point out different temporal responses. Our description provides the time-dependent spatial distribution of the electric field around metallic nano-objects of arbitrary geometries which is the first step to describe light-matter interaction in recently developed laser-driven femtosecond electron nanosources or recent results in ultrafast nanoplasmonics.