  This paper explores the time-domain equations of noble metals, in which Drude
model is adopted to describe the dielectric constant, to implement
three-dimensional particle-in-cell (PIC) simulations for the surface plasmon
excitation with the finite-difference time-domain method (FDTD). A
three-dimensional model for an electron bunch movement near the metal film is
constructed, and particle-in-cell (PIC) simulations are carried out with
various metal films of different thicknesses. The frequency of surface plasmon
obtained from PIC simulation is agreed with that from theory. Furthermore, the
surface plasmon wave properties of excitation and propagation with the metal
film is summarized by PIC results.
