Enhancement of the magneto-optical Kerr rotation in nonlinear optical response

Using an electronic theory we calculate the magneto-optical Kerr rotation in Second-Harmonic Generation (SHG). We derive Fresnel's formulas for the nonlinear optical response. Mathematical details of the derivation are given. For the longitudinal and polar Kerr configuration and for arbitrary angles of incidence it is found that the Kerr angle in SHG may be enhanced by up to one order of magnitude compared to the linear Kerr angle. This enhancement is caused by interband and intraband transitions (plasmons) which in the linear case suppress the Kerr rotation in the optical range. Our results will be useful for a microscopic study of 2D magnetism.Paper presented at the 129th WE- Heraeus-Seminar on Surface Studies by Nonlinear Laser Spectroscopies, Kassel, Germany, May 30 to June 1, 1994