Analytical expressions for spectral dependences of silver, gold, copper and aluminum dielectric permittivity

In this work, the analytical expressions describing experimental data of silver, gold, copper and aluminum dielectric permittivity in a wide spectral range are presented. A comparison of samples production techniques, the measurement methods and the experimental data of different authors led to the conclusion that the most valid data are given by McPeak et al. (ACS Photonics 2(3), 2015, pp. 326–333) and Babar et al.(Appl. Opt. 54(3), 2015, pp. 477–481), which are close to each other. Thus, the analytical expressions for silver, gold, copper and aluminum dielectric permittivity spectral dependences are based on it. The spectral range in which the dielectric permittivity is represented by the corresponding analytical expression is divided into several intervals. There is a specific function for each wavelength range.