Optical Parameters of Aluminum Alloy Samples Irradiated by High Current Relativistic Electron Beams

The aluminum alloys D16, D16AT are widely used as construction materials in the aircraft industry. Questions connected with the enhancement of the properties of the construction elements made of the alloys through surface modification are of great interest now. The objects of the study in our paper are the samples of the aluminum alloy D16AT subjected to irradiation by high-current relativistic electron beams. Leaving aside the material science aspects, in this work we focused on modeling the optical properties of the samples. The problem is relevant because optical methods for surface analysis have become widespread due to their versatility and efficiency. Through the treatment of the preliminary measured ellipsometry data, we obtain the optical constants of the samples and their dispersion in the visible region of wavelength. The method used consists of an approximation of the reflection coefficient calculated from the ellipsometry data by finding the values of the parameters in the model. The last is performed by the least squares method. The reflection coefficient is assumed to correspond to the semibounded uniaxial medium with the optical axis perpendicular to the interface between the medium and the homogeneous and dielectric ambient medium. The dielectric function of the semibounded medium is approximated by the Drude-Lorentz model. The possibility of birefringence of the samples caused by the irradiation with electron beams is discussed.