Optical properties of relaxor ferroelectric crystal: Pb(Zn1/3Nb2/3)O3-4.5 % PbTiO3

High quality Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 single crystal sample with the stable polarization (well poled) were used for the optical measurements in this work. For the single crystal, poled along ⟨111⟩ direction, the wavelength dependence of the refractive index (n1 and n3) was measured by the Minimum Deviation Method. The Sellmeier optical coefficients, Eo=5.25eV, λo=0.236μm, So=0.7×1014m−2 and Ed=20.48eV for n3, and Eo=5.46eV, λo=0.227μm, So=0.8×1014m−2 and Ed=22.52eV for n1, of the PZN-PT, were obtained through fitting the single-term oscillator equation. The effects of crystal-lattice distortion and poling direction on optical properties of crystal were discussed.