Visible and near UV light-induced scattering of LiNbO₃:Fe crystals and material characterization

Abstract

We present an experimental study of reconstructing parasitic gratings that produce simultaneous wide-angle polarization-anisotropic and -isotropic light induced scattering. The gratings were recorded in lithium niobate crystals doped with iron (LiNbO3:Fe) using an ordinary-polarized pump beam in the visible and the near UV spectral ranges. The reconstruction was performed at different readout angles, wavelengths and linear polarization states. The main features of reconstructing the parasitic gratings at different readout conditions are qualitatively explained by a simple phenomenological model based on the Ewald sphere construction. The obtained results and the scattering pattern were applied to determine the birefringence, its sign and further to estimate the relative contribution of diffusion and bulk photovoltaic effect to the photorefractive effect, as well as the ratios of product of the Pockels and the photovoltaic tensors components that contribute to the readout of the gratings at different readout polarizations.

A Comprehensive Study of Photorefractive Properties in Poly(ethylene glycol) Dimethacrylate— Ionic Liquid Composites

“…The seed scatterers might be defects, imperfections and/or optical inhomogeneities within the medium. Therefore, light-induced scattering is a general phenomenon that occurs in virtually all media for which refractive-index changes occur when irradiated with a coherent beam [ 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. The presence of these PGs hinders the applicability of elementary gratings by corrupting the optical quality of the system, e.g., by reducing the signal to noise ratio.…”