Based On The Physical Absorption And Film Thickness Of The Precious Metal Dielectric Parameters Lorentz-Drude Model Optimization Analysis

Surface Plasmon Technology Surface Plasmon Polariton is a very hot research topic, and the nanoscale precious metal film which used in Surface Plasmon also has a very wide range of applications. The Dielectric Parameter of precious metals is a key factor to the performance of micro and nano devices, it can identify and express the optical properties of materials uniquely. Many researches found that the complex Dielectric Parameters show a large fluctuation with the change of working wavelength; this will seriously affect the physical quantities such as Surface Plasmon propagation length. In visible and ultraviolet region, people have questioned dielectric parameters’reliability of the Drude model and Lorentz_Drude model. Therefore, it’s urgent to express the exact Dielectric Parameters of precious metal.Based on Drude model, we use the least square error to matching experimental data of gold, silver and copper in200nm to2000nm, optimizing two important parameters, Plasma Frequency and Free Electron Relaxation Time. Using the optimized Plasma Frequency, we obtain Electron Effective Mass and compare it with other theories calculation, which confirms the correctness of the work. The Drude model ignores the bound electron transitions and other effects impact on the Dielectric Constant, So that the Dielectric Constant of precious metals have a large error in the200nm-700nm UV and visible region with the experimental data. And we made a deep analysis of the metal film’s physical effects when the incident light is200nm-700nm, Such as the Bound Electron Interband Transition. Adjust Resonance Point, Damping Coefficient and Power Factor of L_Drude model based on absorption and loss, made L_Drude model curve are perfectly consistent with experimental data of three kinds of precious metals, provide the accurate dielectric constant data.Finally, in view of surface effect, volume effects, and quantum size effect of the Nanoscale precious metal thin film, it have new characteristic that are different from the conventional bulk metal. So the influence of metal film thickness changes on dielectric constant was studied. The article based on revised F-S model and M-S model discusses the relationship between film thickness and the Dielectric Constant, using the relationship between conductivity and film thickness. Free electron relaxation time is the link between them. Provides a powerful data support for using the precious metal thin film under different thickness.