Sc:In:Fe:LiNbO3晶体的生长及全息关联存储的研究

在Fe:LiNbO3中掺进Sc2O3和In2O3采用Czochralski技术生长Sc:In:Fe:LiNbO3晶体.测试Sc:In:Fe:LiNbO3晶体的红外光谱和抗光致散射能力.Sc(1mol;):In(2mol;):Fe:LiNbO3晶体OH-吸收峰移到3508cm-1,抗光致散射能力比Fe:LiNbO3晶体提高二个数量级.对Sc(1mol;):In(2mol;):Fe:LiNbO3晶体OH-吸收峰移动机理和抗光致散射能力增强的机理进行讨论.以Sc(1mol;):In(2mol;):Fe:LiNbO3晶体作存储元件,以Cu:KNSBN晶体作为位相共轭镜进行全息关联存储,试验结果表明全息关联存储的成象质量高、图象清晰完整、噪音小.     

不同Li/Nb比Mg:In:Fe:LiNbO3晶体的光折变性能研究

采用提拉法生长了不同Li/Nb比(Li/Nb=0.85,0.94,1.05,1.20,1.38)的Mg:In:Fe:LiNbO3(LN)单晶.测试了Mg:In:Fe:LN晶体的红外透射光谱,紫外吸收光谱,抗光致散射能力,响应时间和指数增益系数.实验结果显示:Li/Nb=0.85晶体的OH-吸收峰在3481cm-1附近, Li/Nb=0.94、1.05、1.20的晶体的OH-吸收峰在3505cm-1附近,而Li/Nb=1.38晶体的OH-吸收峰有三个,分别在3466cm-1、3481cm-1和3518cm-1附近.随着Li/Nb比的增大,晶体的紫外吸收边发生紫移,抗光致散射能力增强,响应速度加快,指数增益系数增大.结果表明:Li/Nb=1.38的晶体是性能最为优良的光折变晶体材料.     

In:Ce:Cu:LiNbO3晶体的生长及存储性能研究

在Ce∶Cu∶LiNbO3晶体中掺进In2O3,用CZ法首次生长In∶Ce∶Cu∶LiNbO3晶体.对晶体的抗光折变能力、红外光谱、指数增益系数、衍射效率和响应时间进行了测试,结果表明:In(3mol;)∶Ce∶Cu∶LiNbO3晶体的抗光折变能力比Ce∶Cu∶LiNbO3提高两个数量级,其OH-吸收峰由LiNbO3的3484 cm-1移到3508 cm-1,响应速度比Ce∶Cu∶LiNbO3晶体快三倍.对In∶Ce∶Cu∶LiNbO3晶体抗光折变能力提高的机理、红外光谱OH-吸收峰紫移的机理进行了研究.     

Scx:Fey:Cuz:LN晶体的生长及非挥发性全息存储的研究

本文首次采用Czochralski法生长优质的Scx:Fey:Cuz:LN (x=0,1;, 2;, 3;, 3.5;, y=0.1;, z=0.06;)晶体.测试了晶体抗光致散射能力,以二波耦合光路测试晶体的衍射效率、写入时间和擦除时间,计算光折变灵敏度和动态范围.结果表明:Sc(2mol;):Fe:Cu:LN和Sc(3mol;):Fe:Cu:LN晶体抗光致散射能力比Fe:Cu:LN晶体高两个数量级以上,Scx:Fey:Cuz:LN晶体的写入速度、光折变灵敏度和动态范围等全息存储性能优于Fe:LN晶体.首次采用氪离子激光(482.0 nm,蓝光)作开关光,氦氖激光(632.8 nm,红光)做记录光,以Sc:Fe:Cu:LN晶体作为双光子全息存储记录介质,实现了双光子全息存储固定(非挥发性全息存储).     

Sc:Fe:LiNbO3晶体的生长和光学性能研究

研究双掺Fe(0.03wt;Fe2O3)和Sc(0,1,2,3mol;)铌酸锂晶体全息存储性能.通过晶体红外光谱测试发现:Sc:Fe:LiNbO3晶体中Sc的掺杂浓度超过3mol;时,Sc:Fe:LiNbO3晶体的O-H吸收峰的位置从低掺杂时的3484cm-1移动到3508cm-1.采用光斑畸变法测得(3mol;)Sc:Fe:LiNbO3晶体抗光损伤能力为3.3×103 W/cm2,比Fe:LiNbO3提高了二个数量级.晶体的红外吸收光谱和抗光损伤能力显示:Sc的掺杂浓度为3mol;时具有明显的阈值特征.采用波长为632nm的He-Ne激光器作为光源,通过二波耦合方法测试晶体全息存储性能.实验表明:在一系列Sc:Fe:LiNbO3晶体中,Sc(2mol;):Fe:LiNbO3晶体能获得最佳的光折变灵敏度和动态范围.     

不同Li／NbZr：Fe：LiNbO3晶体的生长及光折变效应的研究

采用Czochralski技术生长不同Li/Nb双掺杂Zr:Fe:LiNbO3晶体,测试了晶体的光学均匀性和抗光折变能力.Zr:Fe:LiNbO3晶体双折射梯度比Fe:LiNbO3晶体降低一个数量级,抗光折变能力比Fe:LiNbO3晶体提高一个数量级,发现Zr4 在LiNbO3中具有抗光折变能力.采用二波耦合光路测试不同Li/Nb的Zr:Fe:LiNbO3晶体的衍射效率、响应时间、擦除时间并计算了动态范围和灵敏度,Zr:Fe:LiNbO3晶体的响应速度,灵敏度和动态范围都比Fe:LiNbO3晶体高,它的全息存储性能优于Fe:LiNbO3晶体.     

双掺杂铌酸锂晶体的生长及其光折变性质

采用提拉法以固液同成分配比(Li2CO3/Nb2O5＝48.6/51.4)生长了Fe掺杂及(Zn,Fe)、(Mg,Fe)和(Ce,Fe)双掺杂LiNbO3(LN)单晶.Ce:Fe:LiNbO3晶体的质量,指数增益系数和衍射效率皆高于Fe:LiNbO3晶体.所测得(Zn,Fe):LN、(Ce,Fe):LN、(Mg,Fe):LN和Fe:LiNbO3晶体的抗光致散射能力分别为8.2×103,3.2×102,8.3×102和1.2×102W/cm3;在488nm光进行的光折变实验中还原处理后的(Ce,Fe):LiNbO3晶体具有最高的二波耦合增益系数,为40.2cm-1,其全息衍射效率可达82.2%;实验结果表明(Zn,Fe):LiNbO3和(Mg,Fe):LiNbO3具有抗光散射能力强,响应时间短的特点,而(Ce,Fe):LiNbO3的增益系数和衍射效率均为最高,明显优于Fe:LiNbO3晶体.     

Zn∶In∶LiNbO3晶体抗光损伤性能的研究

在LiNbO3中掺进ZnO和In2O3以Czochralski技术生长Zn∶In∶LiNbO3晶体.采用光斑畸变法测试Zn∶In∶LiNbO3晶体抗光损伤能力.Zn∶In∶LiNbO3晶体抗光损伤能力比LiNbO3晶体提高二个数量级.测试晶体的红外光谱,Zn∶In∶LiNbO3晶体吸收峰的位置相对LiNbO3晶体发生紫移,且随着Zn2+和In3+浓度增加紫移程度增加.晶体的倍频性能(相位匹配温度和倍频转换效率)研究表明:Zn∶In∶LiNbO3晶体相位匹配温度在室温附近.并研究了Zn∶In∶LiNbO3晶体抗光损伤机理和OH-吸收峰紫移的机理.     

In∶Ce∶Cu∶LiNbO_3晶体的生长及存储性能研究

在Ce∶Cu∶LiNbO3 晶体中掺进In2 O3 ,用CZ法首次生长In∶Ce∶Cu∶LiNbO3 晶体。对晶体的抗光折变能力、红外光谱、指数增益系数、衍射效率和响应时间进行了测试 ,结果表明 :In(3mol% )∶Ce∶Cu∶LiNbO3 晶体的抗光折变能力比Ce∶Cu∶LiNbO3 提高两个数量级 ,其OH-吸收峰由LiNbO3 的 3484cm-1移到 35 0 8cm-1,响应速度比Ce∶Cu∶LiNbO3 晶体快三倍。对In∶Ce∶Cu∶LiNbO3 晶体抗光折变能力提高的机理、红外光谱OH-吸收峰紫移的机理进行了研究     

In:Er:LiNbO3晶体生长及光损伤性能研究

在LiNbO3晶体中掺入In2O3和Er2O3,利用提拉法生长了In:Er:LiNbO3晶体,获得了In和Er在晶体中的分凝系数.通过测试晶体的吸收光谱和抗光损伤能力,确定In:Er:LiNbO3晶体中In的掺杂阈值浓度为～3mol;,In(3mol;):Er:LiNbO3晶体的抗光损伤能力比Er:LiNbO3提高3个数量级以上.研究了In的掺入使Er:LiNbO3晶体的吸收边移动和抗光损伤能力提高的机理.     

Structure and optical damage resistance of In:Yb:Er:LiNbO3 crystals

A series of In:Yb:Er:LiNbO₃ crystals have been grown. The UV‐Vis absorption spectra and Infrared (IR) transmission spectra were measured and discussed in terms of the spectroscopic characterizations and the defect structure of the In:Yb:Er:LiNbO₃ crystals. The optical damage resistance was characterized by the transmitted beam pattern distortion method. The optical damage resistance of In (3.0mol %):Yb:Er:LiNbO₃ crystal is one order of magnitude higher than that of other crystal. The dependence of the optical damage resistance on the defect structure was studied. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Optical damage resistance of Mg:Ce:Fe:LiNbO3 crystals

Mg:Ce:Fe:LiNbO₃ crystals were prepared with fixed concentrations of Fe₂O₃ and CeO₂, and differing concentrations of MgO by the Czochralski technique. Their infrared transmission spectra were measured in order to investigate their defect structures and their optical damage resistance was characterized by the photoinduced birefringence change and transmission facula distortion method. The optical damage resistance of Mg:Ce:Fe:LiNbO₃ crystals increases remarkably when the concentration of MgO exceeds a threshold concentration. The dependence of the optical damage resistance on the defect structure of Mg:Ce:Fe:LiNbO₃ crystals is discussed in detail. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Mg:In:Er:LiNbO3晶体生长及波导基片光损伤的研究

在LiNbO3中掺进MgO,In2O3,Er2O3以Czochralski技术系统生长了Mg(3mol;):In(1mol;):Er(1mol;):LiNbO3,Mg(3mol;):In(2mol;):Er(1mol;):LiNbO3,Mg(3mol;):In(3mol;):Er(1mol;):LiNbO3晶体.Mg(3mol;):In(3mol;):Er(1mol;):LiNbO3晶体荧光光谱表明4I13/2→ 4I15/2(1.53μm)易实现激光振荡.采用质子交换工艺制作Mg:In:Er:LiNbO3晶体波导基片并以m线法研究Mg:In:Er:LiNbO3晶体波导基片的光损伤.发现抗光损伤能力依次为:Mg:In(3mol;):Er:LiNbO3＞Mg:In(2mol;):Er:LiNbO3＞Mg:In(1mol;):Er:LiNbO3>Er:LiNbO3.以锂空位模型研究Mg:In:Er:LiNbO3晶体抗光损伤能力增强的机理.     

In doping effect on optical properties in Zn:In:Fe:LiNbO3 crystals

A series of Zn:In:Fe:LiNbO₃ crystals were prepared by Czochralski method. The crystal composition and defect structure were analyzed by ICP‐OE/MS, UV–vis and IR spectroscopy. The results show that with increasing In³⁺ doping concentration in melt, the segregation coefficients of both Zn and In ions decrease. The optical damage resistance of Zn:In:Fe:LiNbO₃ crystals was studied by the transmitted beam pattern distortion method. It is found that the optical damage resistance of Zn:In(3mol%):Fe LiNbO₃ crystals is two orders of magnitude higher than that of Zn:Fe:LiNbO₃. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

大尺寸掺钕和掺铥铝酸钇晶体的生长和退火技术

通过分析铝酸钇(YAP)晶体产生孪晶、开裂、色心和弥散性散射的原因,探讨了克服这些缺陷和问题的技术途径.采用提拉法生长了b轴方向的掺钕和掺铥铝酸钇(Nd:YAP和Tm:YAP)晶体,通过温场系统、生长工艺参数和切割工艺的优化,克服了晶体开裂的问题,晶体直径达到46mm;通过真空退火工艺,既显著减轻了紫外和可见区的色心吸收,又减小了晶体的应力,有助于克服晶体在加工过程中的开裂问题.晶体生长实验和晶体的显微观察表明:YAP晶体中的弥散状散射很可能同熔体中组分的均匀性有关,通过增大晶体的直径,增强强迫对流有助于减轻晶体中的弥散状散射.高质量b轴Nd:YAP和a轴Tm:YAP晶体已分别实现二极管泵浦大于140W的1.079μm和大于10W的1.99μm激光输出.     

Microstructure and optical properties of Zn:Mn:Fe:LiNbO3 crystals

Zn:Mn:Fe:LiNbO₃ crystals were prepared by Czochralski technique. Its microstructure was measured and analyzed by UV‐Vis absorption spectra. The optical damage resistance of Zn:Mn:Fe:LiNbO₃ crystals was characterized by the transmitted beam pattern distortion method. It increases remarkably when the concentration of ZnO is over a threshold concentration. Its value in Zn(7.0 mol%):Mn:Fe:LiNbO₃ crystal is about three orders of magnitude higher that in the Mn:Fe:LiNbO₃ crystal. The dependence of the defects on the optical damage resistance was discussed. The non‐volatile holographic storage was realized in all crystals, and the sensitivity of the Zn(7.0 mol%):Mn:Fe:LiNbO₃ crystal is much higher than that of others. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nd:YAG/Cr4+:YAG键合棒的制作与激光性能

采用直接键合的方法将Nd:YAG激光棒与Cr4+:YAG调Q元件结合在一起,对Nd:YAG棒和Cr4+:YAG在键合前后的激光性能进行了实验比较.结果表明,键合技术能够有效地提高输出能量,压窄脉宽.     

Investigation on the blue photorefractive properties varied with MgO codoping in Ru:Fe:LiNbO3 crystals

Mg:Ru:Fe:LiNbO₃ crystals with various doping concentration of MgO have been grown by Czochralski method. The type of charge carriers and photorefractive properties in Mg:Ru:Fe:LiNbO₃ crystals were measured by two‐wave coupling method using Kr⁺ laser (476 nm) and He‐Ne laser (633 nm) as light sources. We found that holes were the dominant charge carriers under blue light irradiation while electrons were the dominant charge carriers under red light irradiation. Mg²⁺ ions behaved no longer as damage resistant, but promoter to the photorefractive properties at 476 nm wavelength. The photorefractive properties under blue light improved with the increase concentration of Mg²⁺ ions. The enhancement mechanisms of the blue photorefractive were suggested. Experimental results definitely showed that Mg‐doped two‐centre Ru:Fe:LiNbO₃ was a promising blue photorefraction material for holographic volume storage.     

Growth and photorefractive properties of Mg:Ce:Cu:LiNbO3 crystals grown by Czochralski method

In this paper, photorefractive properties of Mg:Ce:Cu:LiNbO₃ crystals were studied. The crystals doped with different concentration of Mg ions have been grown by the Czochralski method. Mg concentrations in grown crystals were analyzed by an inductively coupled plasma optical emission spectrometry (ICP‐OE/MS). The crystal structures were analyzed by the X‐ray powder diffraction (XRD), ultraviolet‐visible (UV‐Vis) absorption spectra and infrared (IR) transmitatance spectra. The photorefractive properties of crystals were experimentally studied by using two‐beam coupling. In this experiment we determined the writing time, maximum diffraction efficiency and the erasure time of crystals samples with He‐Ne laser. The results showed that the dynamic range (M/#), sensitivity (S) and diffraction efficiency (η) were dependent on the Mg doping concentration, and the Mg(4.58mol%):Ce:Cu:LiNbO₃ crystal was the most proper holographic recording media material among the six crystals studied in the paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)