Linear electro-optic properties of relaxor-based ferroelectric 0.24Pb(In_1/2Nb_1/2)O₃-(0.76 - X)Pb(Mg _1/3Nb_2/3)O₃-xPbTiO₃ single crystals

Linear electro-optic properties of 0.24Pb(In_1/2Nb _1/2)O₃-(0.76 - x)Pb(Mg_1/3Nb_2/3) O₃-xPbTiO₃ single crystals, with compositions in the rhombohedral, morphotropic phase boundary (MPB) and tetragonal phases, have been investigated. Very large effective electro-optic coefficient γ c (204 pm/V) was observed in a crystal with the MPB composition when it is poled along [001]. The rhombohedral phase (x = 0.27 and 0.30) single crystals poled along [111] direction and tetragonal phase (x = 0.39) single crystal poled along [001] direction are in single domain, and their electro-optic coefficients (γ c = 76, 94, and 43 pm/V for the crystals with x = 0.27, 0.30, and 0.39, respectively) were found to be much higher than that of traditional electro-optic single crystal LiNbO₃ (γ c = 19.9 pm/V). The electro-optic coefficients of the single crystal in the rhombohedral phase have excellent temperature stability in the experimental temperature range of 10-40°C. The half-wave voltage V π was calculated to be much lower (less than 1000 V) than that of LiNbO₃ single crystal (2800 V). These superior properties make the ternary relaxor-PT single crystals very promising for electro-optic modulation applications.