Pure lithium tantalite ceramic powders were synthesized by a molten salt method with Li2CO3 and Ta2O5 as reactants and LiCl as flux. The products were characterized by DSC, XRD and SEM techniques. The results show tha...Pure lithium tantalite ceramic powders were synthesized by a molten salt method with Li2CO3 and Ta2O5 as reactants and LiCl as flux. The products were characterized by DSC, XRD and SEM techniques. The results show that the pure LiTaO3 powder is rhombohedral system with space group of R3c. The particle sizes are influenced by the synthesis temperature. The particle size increases with reaction temperature.展开更多
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...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.展开更多
We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. U...We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.展开更多
In our experiments,we used congruent samples of 1 mm thickness,single crystal LiTaO_(3).The samples were implanted at room temperature(RT)by 3.25 MeV Fe,6 MeV Xe,1 MeV Bi ions respectively,with projected ion ranges of...In our experiments,we used congruent samples of 1 mm thickness,single crystal LiTaO_(3).The samples were implanted at room temperature(RT)by 3.25 MeV Fe,6 MeV Xe,1 MeV Bi ions respectively,with projected ion ranges of 1.36,1.23,0.12m calculated by SRIM2008.Note that inert ion Xe is chosen for eliminating the potential effects of new phases resulting from chemical process during implantation,compared to metal ion Fe and Bi.The ion fluences were varied between 1×10^(12) and 2×10^(15) cm^(−2).The optical transmission spectra of the implanted samples were measured by PerkinElmer Lambda 900 UV/VIS/NIR Spectrometer with a scanning step length of 1 nm.During measurement,the incidence non-polarized light was perpendicular to the surfaces of the samples.The surface morphology of samples was characterized by OM and AFM.Rutherford backscattering-channeling(RBS-c)and XRD were used to examine ion-induced structural changes in samples.展开更多
A promising method of ferroelectric domain inverted structures was demonstrated, which allows us to fabricate thicker domain inverted patterns by applying a lower external electric field in LiTaO3 crystal. The externa...A promising method of ferroelectric domain inverted structures was demonstrated, which allows us to fabricate thicker domain inverted patterns by applying a lower external electric field in LiTaO3 crystal. The external field for the domain reversal of the 1.5 mm thick LiTaO3 at 500 ℃ was only 6 V·mm-1, which is lower by three orders of magnitude than that in LiTaO3 crystal at room temperature. The process of the domain inversion structure was also studied. The fabrication techniques are based on controlled temperature and field duration time.展开更多
文摘Pure lithium tantalite ceramic powders were synthesized by a molten salt method with Li2CO3 and Ta2O5 as reactants and LiCl as flux. The products were characterized by DSC, XRD and SEM techniques. The results show that the pure LiTaO3 powder is rhombohedral system with space group of R3c. The particle sizes are influenced by the synthesis temperature. The particle size increases with reaction temperature.
基金Project supported by the National Natural Science Foundation of China （Grant No. 51202045）, the Postdoctoral Science Foundation of Heilongjiang Province, China, and the Fundamental Research Funds for the Central Universities of Ministry of Education of China （Grant No. HIT. NSRIF. 2013004）.
文摘We have grown triply doped Mg:Fe:Mn:LiTaO3 crystals with near stoichiometry using the top seeded solution growth technique. The defect structure was investigated by infrared absorption spectra and Curie temperature. Using a blue laser as the source, excellent photorefractive properties were obtained. Nonvolatile holographic storage properties were investigated using the dual wavelength technique. We got a very high fixed diffraction efficiency and nonvolatile holographic storage sensitivity. The blue light has more than enough energy to excite holes of deep(Mn) and shallow(Fe) trap centers with the same phase, which enhance dramatically the blue photorefractive properties and the nonvolatile holographic storage. Mg2+ ion is no longer damage resistant at blue laser, but enhances photorefractive characteristics.
文摘In our experiments,we used congruent samples of 1 mm thickness,single crystal LiTaO_(3).The samples were implanted at room temperature(RT)by 3.25 MeV Fe,6 MeV Xe,1 MeV Bi ions respectively,with projected ion ranges of 1.36,1.23,0.12m calculated by SRIM2008.Note that inert ion Xe is chosen for eliminating the potential effects of new phases resulting from chemical process during implantation,compared to metal ion Fe and Bi.The ion fluences were varied between 1×10^(12) and 2×10^(15) cm^(−2).The optical transmission spectra of the implanted samples were measured by PerkinElmer Lambda 900 UV/VIS/NIR Spectrometer with a scanning step length of 1 nm.During measurement,the incidence non-polarized light was perpendicular to the surfaces of the samples.The surface morphology of samples was characterized by OM and AFM.Rutherford backscattering-channeling(RBS-c)and XRD were used to examine ion-induced structural changes in samples.
基金Project supported by the National Natural Science Foundation of China (60544004,90501004) and Program for Changjiang Scholars and Innovative Research Team in University
文摘A promising method of ferroelectric domain inverted structures was demonstrated, which allows us to fabricate thicker domain inverted patterns by applying a lower external electric field in LiTaO3 crystal. The external field for the domain reversal of the 1.5 mm thick LiTaO3 at 500 ℃ was only 6 V·mm-1, which is lower by three orders of magnitude than that in LiTaO3 crystal at room temperature. The process of the domain inversion structure was also studied. The fabrication techniques are based on controlled temperature and field duration time.
