Optical Second-Harmonic Generation from Jellium. The Nonlinear Energy Reflection Coefficient as a Function of the Angle of Incidence

Abstract

Within the last twenty years optical second-harmonic processes in centrosymmetric metals have been studied intensively [1,2]. Especially, calculations of the nonlinear energy reflection coefficient, a quantity adequate for comparison to experimental data, have attracted a great deal of attention. The large optical response from the surface (selvedge) region stems from the breaking of the inversion symmetry of the crystal lattice and from the pronounced variation of the electron density. For optical frequencies in the vicinity of the plasma edge one expects that the nonlinear response in free-electron-like metals is dominated by the excitations of collective modes.