Precise determination of full matrix of piezo-optic coefficients with a four-point bending technique: the example of lithium niobate crystals

A recently proposed technique representing a combination of digital imaging laser interferometry with a classical four-point bending method is applied to a canonical nonlinear optical crystal, LiNbO3, to precisely determine a full matrix of its piezo-optic coefficients (POCs). The contribution of a secondary piezooptic effect to the POCs is investigated experimentally and analyzed theoretically. Based on the POCs thus obtained, a full matrix of strain- optic coefficients (SOCs) is calculated and the appropriate errors are estimated. A comparison of our experimental errors for the POCs and SOCs with the known reference data allows us to claim the present technique as the most precise. (C) 2014 Optical Society of America