Effect of intrinsic surface roughness and other decay processes on surface plasmon polariton resonance halfwidth

A comparative study of surface plasmon polaritons (SPPs) on thin Ag films of varying intrinsic surface roughness is conducted using three complementary spectroscopies: the attenuated total reflection (ATR), the forward scattering (FS) and the photoacoustic attenuated total reflection (PA-ATR). The differences in the resonance coupling obtained in the three methods, particularly the resonance halfwidth, are analyzed to account for the decay processes involved in each spectroscopy. The role played by surface roughness interaction in either decreasing or increasing the surface plasmon polariton wavevector is discussed. The PA-ATR is employed to obtain an estimate of the contribution of the multiple scattering and directional scattering processes to the total attenuation of the SPP