Femtosecond imaging of spatial deformation of surface plasmon polariton wave packet during resonant interaction with nanocavity

Abstract The spatiotemporal dynamics of a surface plasmon polariton (SPP) wave packet (WP) that interacts with plasmonic nanocavity on metal are investigated via femtosecond time-resolved two-photon fluorescence microscopy and numerical calculations. nanocavity, which consists metal–insulator–metal (MIM) laminar structure (longitudinal length: ∼100 nm), behaves as subwavelength meta-atom possessing discretized eigenenergies. When chirp-induced femto-second SPP WP is incident the only spectral component matching particular eigenenergy transmitted to continue propagation surface. This clipping induces spatial peak shift in WP. can be controlled by tuning or chirp.