Localization of pulse-modulated surface-plasmon-polariton wave guided by a planar silicon/silver interface

The finite-difference time-domain method was employed to simulate the propagation of a pulse-modulated surface-plasmon-polariton (SPP) wave along a planar silicon/silver interface in the near-infrared spectral regime. The signal energy on the silicon side varies with the carrier frequency, decreases with the propagation distance, and fans away from the interface as the propagation distance increases. Yet a large fraction of the signal energy on the silicon side is confined to within 250 nm of the interface even for a propagation distance of 800 nm.