Optical analysis of photoemission

The role of classical optics in the process of photoemission from thin films is analyzed. The generation of excited electrons throughout the film is assumed to be proportional to the divergence of the Poynting vector in the film. The film and substrate are allowed uniaxial optical anisotropy, with the optic axis normal to the plane of the film. The main results of the analysis, expressions for the reflectance, transmittance, and divergence of the Poynting vector in the film, are valid for all angles of incidence and arbitrary values of the dielectric functions of the nonabsorbing initial medium, film, and substrate. Expressions for the quantum yield are obtained with the aid of a simple function that describes the diffusion and escape of the excited electrons. Some applications to photoemission from metals in the vacuum-ultraviolet region are discussed.