Linear and nonlinear optical properties of Tellurium Vanadate (Te2V2O9)

We report here the structure property correlation of Tellurium Vanadate (Te2V2O9) through various optical and vibrational spectroscopic investigations. Pure phase polycrystalline powder of Te2V2O9 was prepared by solid state reaction technique. Phase purity of the sample was confirmed by Powder X-Ray diffraction and the microstructural investigation was analyzed using Scanning Electron Microscopy. Raman microscopy was employed to validate the molecular structure. Diffused Reflectance and Photoluminescence spectroscopy were employed to study the optical properties. Because of non-centrosymmetry, we also observed second harmonic generation in tellurium vanadate. Subsequently, third order nonlinear optical response of Te2V2O9 was probed using open-aperture Z-scan technique estimating the nonlinear absorption coefficient to be 1e-10 mW(-1). The mechanism of nonlinear absorption was deduced to be a two-photon absorption process. This was ascertained through existence of excited states predicted from electronic structure of Te2V2O9 using Density Functional Theory. It is also noteworthy to highlight that Te2V2O9 possess higher nonlinear optical coefficient than other vanadate compounds reported in literature. (C) 2017 Elsevier B.V. All rights reserved.