Influence of Fabrication Methods of Gold and Silver Layers on Surface Plasmon Polaritons Propagation Length

We present an experimental study of surface plasmon polaritons (SPPs) propagation length (L SPP ) on polycrystalline metal (gold and silver) films, fabricated by evaporation and sputtering techniques on glass substrates. For the excitation of SPPs, polymer grids on the sample surface are used. The SPPs are excited by a He-Ne (633 nm) and the L SPP are measured by grating-coupling method and the leakage radiation microscopy. Dependence of L SPP on the film thickness is also investigated. The longer L SPP is observed with evaporation technique in comparison to the sputtering technique for the silver films. On the other hand, sputtering technique provides longer L SPP for the gold films. Additionally, atomically flat crystalline gold flakes are also considered for the SPPs evaluation. The L SPP estimation on these flakes is carried out for light wavelength of 633 and 800 nm.