Numerical study of surface plasmon resonance in rough thin films in Kretschmann configuration

Abstract

Despite the existence of ultra-precise technology, there still defects in the final quality of the surface of optical components that could affects their performance. In this work, we show a numerical analysis to analyze the effects of the roughness of the conducting and dielectric thin films, deposited over the prism, that constitute the multilayer system responsible of the surface plasmon resonance(SPR) excitation in the Kretschmann configuration. To simulate the optical response of the system, we used the Integral Equation Method and the Lorentz-Drude model. Furthermore, rough surface profiles are generated by a random Gaussian correlation process that obeys an exponential probability density function, whose parameters are the standard deviation of heights &sigma_h and thecorrelation length &delta_c. The results obtained indicate that the SPR angles for the smooth thin films had an angular displacement due to the influence of the thin films roughness. Therefore, roughness insurfaces can modify substantially the location of the SPR angle. These optical properties could be useful in a large number of applications in various fields of science and technology, such as plasmonic sensing.