Surface-plasmon-based electron acceleration

In this paper, we describe a surface-plasmon-based electron acceleration model, the results of which were supported by our recent experimental observations [S. E. Irvine et al., Phys. Rev. Lett. 93, 184801 (2004)]. The model incorporates femtosecond electromagnetic field dynamics and nonlinear electron photoemission characteristics of metallic surfaces. To account for the electromagnetic field structure in space and time, we numerically solve Maxwell's equations in two dimensions. Photoelectron emission is treated quasiclassically in accordance with empirical multiphoton statistics, whereas electron dynamics and energy gain are governed by the Lorentz force. Various aspects of the acceleration mechanism are discussed including surface plasmon coupling and evanescent decay, kinetic energy spectra, angular distributions, angle-resolved energy spectra, and the dependence of maximum energy on the surface electric field.