Piezo-optic and elasto-optic effects in lead molibdate crystals

Piezo-optical and elasto-optical properties of lead molibdate (PbMoO4) crystals are investigated, as determined by the quantum-mechanical ab initio calculation of the full set of elasto-optic, piezo-optic and elastic tensor components. Indicative surfaces are built, which describe the anisotropy of these stress- and strain-optical effects and allow for its rigorous analysis. Maximum values of these properties are determined as well as the geometries of acousto-optic interaction displaying the maximum efficiency. Lead molibdate crystals are found to be characterized by a large piezo-optic efficiency, the maximum change of the optical path (per unit of mechanical stress and specimen length) being calculated to 24.9 Br, which is a much larger value than previously reported for other well-known piezo-optic materials such as LiNbO3, CaWO4 and GaP. It is also shown that a significant rotation (up to several tens of degrees) of the optical indicatrix about the X-3 optical axis is induced by uniaxial pressure or deformation, depending only on pressure (or deformation) direction, which has relevant implications in the design of acousto-optic cells. (C) 2016 Elsevier B.V. All rights reserved.