Interaction of light and surface plasmon polaritons in Ag Islands studied by nonlinear photoemission microscopy

• Surface plasmon polaritons were studied on Ag islands in two photon photoemission microscopy.
• Ag islands were prepared using self-assembly, electron beam lithography, and a focused ion beam.
• The SPP pattern on Ag islands can be described with a simple moiré concept.
• SPP output coupling results in a pattern that can again be described by the moiré effect.

Two photon photoemission microscopy was used to study the interaction of femtosecond laser pulses with Ag islands prepared using different strategies on Si(111) and SiO2. The femtosecond laser pulses initiate surface plasmon polariton (SPP) waves at the edges of the island. The superposition of the electrical fields of the femtosecond laser pulses with the electrical fields of the SPP results in a moiré pattern that is comparable despite the rather different methods of preparation and that gives access to the wavelength and direction of the SPP waves. If the SPPs reach edges of the Ag islands, they can be converted back into light waves. The incident and refracted light waves result in an interference pattern that can again be described with a moiré pattern, demonstrating that Ag islands can be used as plasmonic beam deflectors for light.