Time-resolved imaging of the propagation and interference of isolated ultrashort surface plasmon polariton wave packets is demonstrated using two photon photoemission microscopy. The group- and phase velocity of individual wave packets are determined experimentally. Using two counter-propagating surface plasmon polariton pulses, the transient formation of a standing surface plasmon polariton wave is imaged in time and space. We demonstrate that using a normal incidence geometry in time-resolved photoemission microscopy provides great advantages for in-situ imaging of surface plasmon polaritons in arbitrary plasmonic structures. A simple 1D wave-simulation is used to confirm the experimental results.
- Normal-incidence geometry
- Surface plasmon polariton
- Time-resolved imaging
- Two photon photoemission microcopy