Spatial anisotropy of the linear electro-optic effect in lithium niobate crystals: Analytical calculations and their experimental verification

• Spatial anisotropy of the linear electro-optic effect in lithium niobate is reported.
• Electro-optic anisotropy is studied by interferometric and polarimetric techniques.
• Electro-optic measurements are supplied by relevant analytical calculations.
• Validity of the analytical approaches is proved experimentally.

We demonstrate an experimental verification of analytical approaches used for evaluation of the spatial anisotropy of linear electro-optic effect in crystal materials. The electro-optic measurements have been performed on a series of crystal X/α-cuts (0° < α < 90°) of LiNbO3 crystals to get a cross section of the indicative surfaces. The experimental results are compared with analytical calculations. A fairly good agreement was found between the experiment and calculations for the effective electro-optic coefficients describing both electro-induced optical pathlength and birefringence. The discrepancy between experiment and theory remains within errors of the interferometric or polarization–optical measurements.