Ukrainian Journal of Physical Optics 

Institute of Physical Optics, 23 Dragomanov Str., Lviv 79005, Ukraine

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The combined piezo-electrooptical effect in LiNbO3 and LiTaO3 crystals is studied. It is shown that the mechanical stresses change notably the electrooptical (EO) coefficient r₂₂ of lithium niobate and the coefficient n^e₃r₃₃-n^o₃r₃₃ of lithium tantalate crystals. The largest increment of electrooptical coefficients under the mechanical stresses is observed in LiNbO3 crystals at the experimental geometry of k||Z, E||Y and s||Y. In case of LiNbO3 crystals subjected to the compressing mechanical stress s₂ =2.0*10⁷N/m2, the EO coefficient r₂₂ increases approximately two times, while the half-wave voltage decreases by the same value. The obtained dependence of the angle  x₃ of optical indicatrix rotation under the applied electric field E₁ and the mechanical compressive stress  s₁ testifies a possibility for controlling the optical indicatrix orientation in LiNbO3 crystals in the range of 0-45deg.

Key words: piezo-electrooptical effect, LiNbO3, LiTaO3
PACS: 78.20.Hp

doi 10.3116/16091833/4/1/48/2003