CLASSICAL HYDRODYNAMIC MODEL OF OPTICAL 2ND-HARMONIC GENERATION STUDIED WITHIN THE SEMICLASSICAL INFINITE-BARRIER APPROXIMATION

A theoretical investigation of optical second-harmonic generation from a flat metal surface within the framework of the semiclassical infini te-barrier model with the electrons assumed to be specularly reflected at the metal-vacuum boundary is presented. The metal is assumed to be excited by a single plane wave at the cyclic frequency omega incident from vacuum upon the metal surface. The investigation is carried out with the hydrodynamic model, which is quite appealing because all quan tities can be calculated analytically and presented in an explicit for m. A new explicit expression of the energy-reflection coefficient of s econd-harmonic light is achieved, and it is demonstrated that it is in agreement with the well-known parameterization scheme, in which the s econd-harmonic energy-reflection coefficient is expressed in terms of a surface contribution, described by frequency-dependent parameters a = a(omega) and b = b(omega), and a bulk contribution, described by the parameter d = d(omega).