PROPAGATION CHARACTERISTICS OF SURFACE PLASMON WAVES ON Au, Ag AND Al AT OPTICAL WAVELENGTHS

In this paper the propagation characteristics of Surface Plasmon Waves (SPWs) which exists on noble metals like gold (Au), silver (Ag) and aluminium (Al) due to the formation of Surface Plasmon Polaritons (SPPs), have been evaluated theoretically and simulated with the help of MATLAB programming language. The variation of the propagation constant, the attenuation coefficient and penetration depth inside the metal and the dielectric has been evaluated. The variations of the spot size width with the propagating wavelength also have been determined for the metals. It has been found that highly conducting metals Au and Ag provide a strong confinement to the SPWs than Al at optical frequencies as the spot size width of the former is found to be nearly 10 mu m less than that of the later. The comparative study reveals that metal having higher conductivity can support a more confined SPW, having a lower penetration depth than metals of lower conductivity at terahertz frequencies when its dielectric constant assumes a negative value.