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Forward degenerate four-wave mixing (DFWM) processes are investigated with a femtosecond pulsed laser in lithium niobate crystal doubly-doped with magnesium and iron (LiNbO3:Fe, Mg). The pulse energy dependence reveals a pure third-order nonlinear response, and the third-order nonlinear susceptibility x^(3) in the material is evaluated to be 4.96 × 10^-13 esu. The time-resolved DFWM process shows a response time of x^(3) shorter than 100fs, which is due to the nonresonant electronic nonlinearities. Our results indicate that LiNbO3 crystals have potentials for ultrafast real-time optical processing systems, which require a large and fast x^(3) optical nonlinearity. 相似文献
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研究系数密集间断的边值问题,采用降维方法,使得在数值计算上可实现并行计算,并且收敛性的证明变得很简洁. 相似文献
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级联二阶非线性铌酸锂全光开关的研制 总被引:3,自引:3,他引:0
以基于准位相匹配和频与差频级联二阶非线性[X^(2):X^(2)]基础上的全光开关的理论分析作指导,进行了周期极化铌酸锂晶体(PPLN)和退火质子交换光波导(APE)的实验制备,利用所研制的PPLN-APE器件,以自行研制的工作波长为1.54μm的被动调Q掺钴铝酸镁激光器作为控制光源,以工作波长为1.5μm的连续二极管激光器为信号光源进行了级联二阶非线性全光开关实验。当控制光峰值功率为3kw,信号光功率为1mW时,实现13%的开关效率,分析了进一步提高全光开关性能的途径。 相似文献
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近化学计量比掺镁铌酸锂晶体的抗光折变性能 总被引:3,自引:0,他引:3
应用气相传输平衡技术,我们获得了3种近化学计量比掺镁铌酸锂晶体,晶体的掺镁量接近我们以前提出的第二阈值.在我们实验室所能达到的最大光强26 MW/cm2照射下,在所有近化学计量比掺镁铌酸锂晶片中没有观察到光斑畸变,该光强比同成分铌酸锂晶体所能承受的光强高6个量级,为目前已报道的铌酸锂晶体之最.应用双光束全息写入法测得掺1.0 mol; Mg近化学计量比铌酸锂晶体的光折变饱和值仅有4.6×10-7,比同成分铌酸锂晶体小两个量级,从已有实验数据推测,该晶体的抗光折变能力应当比同成分铌酸锂晶体高9个量级以上. 相似文献
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Nonvolatile two-color holographic recording gated by incoherent ultraviolet (UV) light centered at 365 nm is investigated in near-stoichiometric lithium niobate crystals. The influence of thermal treatment on the two-color recording is studied. The results show that thermal reduction tends to improve the two-color recording performance, whereas thermal oxidation degrades the two-color recording. With an incoherent 0.2-W/cm2 UV gating light and a 0.25-W/cm2 semiconductor recording laser at 780 nm, a two-color recording sensitivity of 4 × 10^-3 cm/J and a recording dynamic range characterized by M/# of 0.12 are achieved in a 2.2-mm thermally reduced near-stoichiometric lithium niobate crystal. We attribute the improvement to the prolonged lifetime of small polarons and the increased absorption at the gating wavelength due to thermal reduction. 相似文献
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采用提拉法生长出尺寸为φ25mm×40mm的透明Er^3+:KLa(WO4)2(简称Er:KLW)晶体,并确定了较佳的生长工艺。X射线粉末衍射分析结果表明该晶体为四方晶系白钨矿结构(I41/a空间群),晶格常数为a=b=0.5444(3)nm,c=1.2120(6)nm。测量了Er:KLW晶体的拉曼谱,发现了380,450和808cm^-1等钨酸根的特征振动峰。测量了晶体的吸收光谱,应用J-O理论计算了晶体中Er^3+离子的强度参量(Ω2,Ω4,Ω6);荧光光谱测量结果表明该晶体在1529nm附近有很强的荧光发射峰,利于产生受激辐射。 相似文献
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通过生长一系列掺钼近化学计量比铌酸锂晶体,研究了晶体的光折变性能,发现在488 nm和532 nm波长辐照下,当Mo的掺入量为0.5mol;时,晶体的光折变灵敏度分别达到0.25 cm/J和0.21 cm/J.此外,极化条件的改变可以缩短晶体在488 nm波长辐照下的光折变响应时间.通过红外光谱、紫外可见吸收光谱和X射线光电子能谱的测试,对掺钼近化学计量比铌酸锂晶体的光折变性能变化的机制进行了研究. 相似文献
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