Nonlinear response of antiferromagnetic films to radiation at oblique incidence

Abstract

The response of an antiferromagnetic film to incident radiation at oblique incidence is studied in the nonlinear regime. For given values of the frequency and incidence angle, the reflectivity of a film of arbitrary thickness is obtained as an implicit function of the incident field amplitude. The compound effect of the incidence angle and field strength on the reflected radiation is studied by means of the analysis of the reflection coefficient calculated for different values of these external variables. We use the physical parameters of the uniaxial Heisenberg antiferromagnet FeF2 to obtain numerical results. It is found that the threshold for nonlinear optical behavior is strongly dependent on the incidence angle.