Peculiar features of surface plasmon-polariton modulation instability in a metal film with varying thickness

摘要

We report on the modulation instability of surface plasmon-polariton wave developed in a thin metal film with varying thickness. It is shown both analytically and numerically that the modulation instability effect can give rise to spatial redistribution and longitudinal localization of surface plasmon-polariton wave energy in subwavelength scale. The frequency, around which modulation instability of surface plasmon polariton wave can be observed, is determined. In this frequency range the propagation of a modulated plasmon wave in a film with increasing thickness is similar to the propagation of modulated light in a dispersion decreasing fiber, enabling generation of high repetition rate ultrashort pulse train.