Linear Electro-optic Effect of 0.88Pb(Zn1/3Nb2/3)O3–0.12PbTiO3 Single Crystal

The linear electro-optic (E-O) coefficients of poled 0.88Pb(Zn1/3Nb2/3)O3–0.12PbTiO3 single crystal were characterized using an automated scanning Mach-Zehnder interferometer and the senarmont compensator method at room temperature. They were obtained at a wavelength of 632.8 nm: r 33=134 pm/V, r 13=7 pm/V, r 51=462 pm/V, and r c=131 pm/V respectively and the refractive indices: n e=2.57 and n o=2.46. The large r 51 coefficient compared with r 33 is caused by the high dielectric constant at perpendicular to the polar-axis compared with the dielectric constant along the c-axis. Comparison with the quadratic E-O coefficients measured at near and above the Curie temperature suggests that the values of the quadratic E-O coefficients measured earlier may be smaller than the intrinsic ones due to the influence of micro-polar regions. The development of an automated scanning Mach-Zehnder interferometer, which is less susceptible to the errors caused by the laser intensity fluctuation and drafting in the optical path length in the system, is also described.