Optical harmonic generation in magnetic garnet epitaxial films near the fundamental absorption edge

Spectra of the second and third optical harmonics generated in epitaxial films of magnetic garnets were studied in the ranges 1.7–3.2 and 2.4–4.2 eV, respectively. A large magnetic contrast was revealed in second-optical-harmonic spectra, which reaches 100% at certain photon energies. By contrast, the symmetry-allowed magnetic contribution to spectra of the third optical harmonic was not found. While linear absorption in ferrite-garnet films grows by two orders of magnitude above the fundamental absorption edge at ∼3.2 eV, the intensity of nonlinear spectra did not reveal any noticeable increase over this spectral range.