Direct evidence of correlation between the second harmonic generation anisotropy patterns and the polarization orientation of perovskite ferroelectric

Abstract

For ferroelectric materials, where the polar state breaks the inversion symmetry, second harmonic generation is a useful tool to prove their ferroelectric properties. However, the correlation between the anisotropy patterns and the polarization orientation of the ferroelectric domains has not been clarified yet. In this work, we systematically investigated this correlation in a typical perovskite oxide ferroelectric, Barium Titanate (BaTiO3) crystal, by second harmonic generation and the piezoresponse force microscopy technique. The evolution of polarization-dependent anisotropy patterns proves that there is a linear relationship between the rotation angle of second harmonic generation anisotropy patterns and the polarization angle of BaTiO3 single crystals. It is a direct evidence illustrating that the polarization of BaTiO3 crystal can be qualitatively identified in 0°–180° by second harmonic generation technology. This work gives a glance at improving a nonintrusive and convenient method to identify the polarization of perovskite ferroelectric materials.

Constraint-free wavelength conversion supported by giant optical refraction in a 3D perovskite supercrystal

“…Wavelength conversion is mediated by the second-order nonlinear susceptibility response χ (2) of the KTN:Li perovskite in its noncentrosymmetric tetragonal 4 mm state. In distinction to single-domain or to quasiphase-matching schemes, the nonlinear process is mediated by a supercrystal with its specific 3D geometry, giant refraction, and underlying ferroelectric domain structure 17,27 . Hence, while giant refraction causes conversion efficiency to be essentially independent of polarization, input angle, and wavelength, the details of the SHG output strongly depend on input parameters and the supercrystal structure.…”

Second Harmonic Generation in Lithiated Silicon Nanowires: Derivations and Computational Methods

“…The dimensions of each parameter are of standard metric system with the reminder that for χ (1) is dimensionless i.e. unity and , χ (2) , χ (3) , χ (4 ) etc. are of the m-th order inverse electric field units i.e.…”

“…A possible alternative for lithiated silicon nanowires other than energy storage devices are applications with second harmonic generation (SHG). It has been well known for over the last two decades that crystalline silicon (c-Si) can experience anisotropic expansion due to polarization from an electric field [3]. More recently it has been shown that certain crystals exposed to lasers has produced anisotropic expansion in certain crystallized lattices that leads to the creation of second harmonic generation [4].…”

Structure demonstration of perovskite oxide and its epitaxial thin films by second harmonic generation

“…The results illustrated that there is a linear re-lationship between the rotation angle of SHG patterns and the polarization angle of BTO crystals. Thus, the polarization direction of BTO crystal, even of other ferroelectric materials, can be qualitatively identified in 0°-180°by SHG technology [11].…”

“…On the other hand, as the simplest example of nonlinear optic process, second harmonic generation (SHG) is a powerful tool to explore the symmetry of noncentrosymmetric structures [9][10][11][12]. It works especially well in terms of surfaces and interfaces where the different media on each side break the inversion symmetry [13], as well as the crystals and films with polar structure [14].…”