In situ monitoring of surface plasmons in single-crystalline Ag-nanowires

We present a two-photon photoemission microscopy investigation of surface plasmon polaritons in single-crystalline Ag-nanowires. When the lateral width of the Ag-nanowires exceeds a certain value, the surface plasmon polariton wave is visualised as a result of interference (beat pattern) between the primary laser pulse and the traveling surface plasmon wave at the sample surface. Continuously reducing the length of the nanowire while maintaining the lateral dimensions unchanged does not lead to changes of the surface plasmon polariton wave.