Metal type Effect on Plasmonic Fiber Properties

Abstract

In this study, the properties of plasmonic fiber have been studied, in which the core is one of the noble metals (Au,Ag,Cu,Al). The modes and the effective refractive index associated with each wavelength were derived using the COMSOL MULTIPHYSICS based on the Finite Element Method. The electrical permetivity was studied using the relationship Lorentz derode to determine the real part for the refractive index and the imaginary part responsible for the attenuation coefficient. Where a frequency range was chosen to hold negative values for the real part. The results show that when drawing the relationship between (εr ) or (εi ) a function of the wavelength that gold has the highest value and then silver, copper and then aluminum, but in the case of (nr ) or (ni ) we notice that aluminum has the highest elements.(neff ) has also drawn as a function of the wavelength, the four metals, and different of the core radius (a=100, 200, 300, 400, 500) for the three modes (LP 01,LP 11,LP 21) and the metal used. It is observed that increasing the mode index increases the lobes where the mode (LP 01) is one spot and the mode (LP11) is two spot and the mode (LP 21) is four spot,where the power index increase is the increase in red and yellow color, and this applies to all modes. In other words, by controlling the radius of the core and wavelength, we can balance the ratio of power that propagation forward and backward. The refractive index (neff) has the highest value at small wavelengths and then begins to decrease with increasing wavelength, and has the highest value in the case of gold, then silver, then copper. Then aluminum, which is less than the rest of the elements.