Domain and domain wall contributions to optical second harmonic generation in thin magnetic films

A symmetry analysis of nonlinear-optical imaging of domains and domain walls in thin magnetic films is presented. Different contributions to the second harmonic (SH) response depending on the local magnitude of the film magnetization M as well as on its spatial derivatives are calculated. The polarization of the SH light is shown to be a sensitive function of the relative weight of different magnetization-induced contributions, the film symmetry, and the type of the domain wall. (C) 1997 American Institute of Physics.