Theoretical Study of Excitation of Surface Plasmon Polaritons Using Silver Metal

This paper reports the excitation of surface plasmon polaritons (SPPs) using silver (Ag) metal. To analyze the excitation of the SPPs, reflection spectra have been extracted and reflection dip is observed which is associated with this phenomenon; metallic film of Ag is used with thickness of about 40 nm, 50 nm, and 60 nm. The reflection corresponding to wavelength is being analyzed by using simulation-based software COMSOL RF module 5.3a, which give information of far and near field which is essential for the confirmation of the excitation of plasmons. It is worth mentioning that at excitation angle 43°, by changing the thickness of metallic film of Ag, the reflection dip varies at spectral ranges 736 to 762 nm that is in the visible part of spectrum or in the NIR region of spectrum where most of the real detectors works well in practical life. In addition, the SPP dispersion coupling on a periodic structured surface is demonstrated in which the coupling points can be seen at specific values ​of energy and wavelength. SPP modes are plotted using SPP scattering curves by converting these curves to an integral multiplier of k_g=2π/Λ , and then in another direction, SPP modes are again plotted for the propagation of SPP for negative k_SPP . The excitation of the SPPs will occur at the overlapping point of light line and k_SPP curve for Ag with a fixed periodicity of 700 nm.