三掺杂化学计量比钽酸锂晶体的非挥发光存储性能

Nonvolatile photorefractive properties of triply doped stoichiometric lithium tantalate single crystals

采用顶部籽晶助熔剂法生长了三掺杂近化学计量比Mg:Fe:Mn:Li Ta O3晶体,通过红外吸收光谱和居里温度研究了晶体缺陷结构.以蓝色激光为光源,获得了优异的光折变性质;采用多波长技术,研究了单晶的非挥发全息存储性能,得到了较高的固定衍射效率和灵敏度.蓝光具有较高能量,足以激发深(Mn)浅(Fe)陷阱中心的空穴,这大大提高了蓝光光折变性质和非挥发存储能力.在蓝色激光下,Mg2+不再是光损伤离子,而可以提高光折变特性.采用476 nm激光记录光栅,633 nm激光读取,在2.0 mol%Mg2+掺杂的晶体中获得了62.5%的固定衍射效率,非挥发全息存储的灵敏度提高到0.335 cm/J.

Triply doped Mg：Fe：Mn：LiTaO3 crystals with near stoichiometry were grown by the top seeded solution growth technique. Defect structure was investigated by infrared absorption spectra and Curie temperature. Using blue laser as light source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated by dual wavelength technique. High fixed diffraction efficiency and sensitivity were acquired. The energy of blue light is high enough to excite holes of deep （Mn） and shallow （Fe） trap centers, which enhance dramatically blue photorefractive properties and nonvolatile holographic storage. Mg^2＋ ion is no longer damage resistant under blue laser, but enhances photorefractive characteristics. Using 476 nm laser to record grating, 633 nm laser as reading light, the fixed diffraction efficiency of 62.5% was obtained in 2 tool% Mg^2＋ doped crystal, the sensitivity of nonvolatile holographic storage was improved to 0.335 cm/J.