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

High quality Pb(Zn1/3Nb2/3)O-3-4.5%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 (n(1) and n(3)) Was measured by the Minimum Deviation Method. The Sellmeier optical coefficients, E-o=5.25eV, lambda(o)=0.236 mu m, S-o=0.7x10(14)m(-2) and E-d=20.48eV for n(3), and E-o=5.46eV, lambda(o)=0.227 mu m, S-o=0.8x10(14)m(-2) and E-d=22.52eV for n(1), 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.