铌锌酸铅-钛酸铅单晶的生长及性能

本文系统地研究了(1-x)Pb(Zn1/3 Nb2/3)O3-xPbTiO3(PZN-PT)单晶的光学透过率与结晶取向和组分的关系,发现四方相单晶的透过率明显大于三方相和准同型相界(MPB).[001]方向极化的四方相PZN-12％PT单晶在0.5～5.8μm的波段范围内,未镀增透膜的晶片透过率约为65％;准同型相界处...

Growth and Properties of Lead Zinc Niobate-Lead Titanate Single Crystals

Transmittance of (1-x)Pb(Zn_1/3Nb_2/3)O₃-xPbTiO₃ (PZN-PT) single crystals was systematically characterized with respect to crystallographic orientation and composition. The results show that the transmittance of tetragonal single crystal is evidently larger than that of rhombohedral and morphotropic phase boundary (MPB) single crystals. Transmittance spectrum of tetragonal PZN-12%PT single crystal poled along [001] direction ranges from 0.5 μm to 5.8 μm, its transmittance without antireflective film is roughly 65%. After poled along [011] direction, the transmittance of PZN-8%PT single crystal in MPB is much higher than that poled along [001] or [111] direction. As the PT content increases, optical band gap of single crystals decreases. Refractive indices of PZN-PT single crystals with different PT content were measured. Just as most compounds with ABO₃ perovskite structure, the refractive indices of PZN-PT single crystals are very large, which decrease rapidly with the increasing wavelength. Refractive index dispersion is obvious, and dispersion equations were fitted. Electro-optic (EO) coefficients were measured by Sénarmont compensator and two-beam interference methods. The EO coefficients of PZN-PT single crystals are very large, which reach maximum in the MPB. The effective EO coefficient of PZN-8%PT single crystal is 460 pm/V after poled along [001] direction, which is higher than 20 times that of widely used LiNbO₃. The effective EO coefficient of PZN-12%PT single crystal is 138 pm/V, which is nearly invariant from 20 ℃ to 80 ℃. Because of the excellent transmittance and outstanding EO properties, PZN-PT single crystals allow of smaller size and lower operating voltage for EO devices.