Generation of sum-frequency waves in the surface layer of a spherical particle

Within the Wentzel–Kramers–Brillouin approximation, a numerical solution was obtained for the problem of the sum-frequency waves generation in a surface optically nonlinear layer of a dielectric spherical particle placed in a dielectric when it is irradiated with two plane elliptically polarized electromagnetic waves. The dependence of the spatial distribution of the generated radiation on the independent components of the nonlinear dielectric susceptibility tensor of the surface layer and on the particle size is analyzed. The differences and similarities of the results obtained on the basis of the Wentzel–Kramers–Brillouin and Rayleigh–Hans–Debye models are highlighted.