Optical second harmonic on oxide interfaces

Discontinuities are the fundamentals of any interface-based device. The rich physics of oxide interfaces lies in the electronic correlations at the boundaries. There, the intrinsic symmetry of the bulk constituent materials is inherently broken. Optical second harmonic generation is, thus, an ideal tool to investigate the manifestations of several effects related to the presence of the interface. Two examples, addressing different issues in different systems, are reviewed here in order to highlight the potential richness of this technique when applied to interface-related phenomena in oxides.