Nonlinear Optics of Ferroelectrics: Towards Nanometers and Picoseconds.

Optical second harmonic generation (SHG) is shown to be a powerful tool for characterizing the main properties and processes in ferroelectrics. In this paper first of all a general phenomenological description is given in order to express the SHG field (intensity) in terms of dielectric polarization. Then specific experimental techniques are described to study crystalline and domain structure of thin ferroelectric films, the bulk and interface ferroelectric and structural phase transitions. Finally SHG is applied to characterize ferroelectric nanostructures and fast polarization switching on nanosecond and picosecond time scales. [ABSTRACT FROM AUTHOR]