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)     

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)     

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)     

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).     

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)     

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.     

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.     

Small-angle X-ray scattering studies of a-Si:C:H

Small-angle X-ray scattering studies have been performed on a series of four a-Si:C:H alloys, prepared by rf glow discharge decomposition of varying proportions of propane and silane, in an attempt to elucidate their mesoscopic structure. The observed broad scattering peak has been interpreted as originating from irregular, elongated voids with a repeat distance of about 20 Å and correlation length of about 25 Å. The implications of this result in explaining the photo-oxidation properties of the material are also discussed.     

Defect structure and optical fixing holographic storage of Mg:Mn:Fe:LiNbO3 crystals

Mg:Mn:Fe:LiNbO₃ crystals were grown by the Czochralski method. The defect structure was analyzed by UV‐vis spectra and IR spectra. The holographic storage of Mg:Mn:Fe:LiNbO₃ crystals was measured by the two color fixed method. The results show that with the increase of MgO doping concentration, the writing time becomes shorter, the dynamic range decreases, photorefractive sensitivity increases and fixing diffraction efficiency decreases. When the MgO doping concentration exceeds 4.5 mol%, the fixing diffraction efficiency approaches zero. The effect of doping Mg ions on the holographic storage properties of Mn:Fe:LiNbO₃ crystals is discussed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Characterization and luminescence of a-Si:H:Cl films

a-Si:H:Cl films have been deposited by glow-discharge and characterized by infrared transmission, optical absorption and photoluminescence. The influence of growth parameters on the H and Cl content has been investigated. The luminescence spectra show that three different radiative transitions can occur, at 0.75, 0.95 and ～1.3 eV. These bands have been interpreted respectively in terms of the following recombinations: defect to defect, defect to band tail, band tail to band tail.     

Improved blue photorefractive properties of near‐stoichiometric LiNbO3:Mn:Fe:Zr crystal

Near‐stoichiometric LiNbO₃ single crystal tri‐doped with ZrO₂, MnO and Fe₂O₃ was grown from Li‐riched melt by Czochralski method. The defect structures and composition of these crystals were analyzed by means of ultraviolet‐visible and infrared transmittance spectra. The appearance of 3466 cm^‐1 peak in infrared spectra showed that the crystal grown from Li‐riched melt was near stoichiometric. The photorefractive properties at the wavelength of 488 nm and 633 nm were investigated with two‐beam coupling experiment, respectively. The experimental results showed that the response speed and sensitivity were enhanced significantly and the high diffraction efficiency was obtained at 488 nm wavelength. This manifested that near‐stoichiometric LiNbO₃:Mn:Fe:Zr crystal was an excellent candidate for holographic storage. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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)     

Electrical properties of semi-insulating CdTe0:9Se0:1:Cl crystal and its surface preparation

CdTe_0.9Se_0.1:Cl crystals doped with chlorine at 5×10¹⁷ cm^?3 level were grown by the vertical Bridgman method. The composition of Se throughout the ingot was nearly constant at x=0.110±0.016. The electrical resistivity of CdTeSe:Cl was 4.5×10⁹ Ω cm. Chemical etchants were employed to obtain stoichiometric and flat surfaces for electrode deposition, and the effects of the etchants on CdTeSe surfaces were analyzed by photoluminescence (PL) and AFM with different bromine concentrations and etching times. The mobility-lifetime products of electron and hole in CdTeSe:Cl crystals were of the order of ～10^?2 cm²/V and its values are greater than those for CdTe crystals. The energy resolution of a CdTeSe:Cl detector was tested using a ²⁴¹Am radioactive source.     

Effect of reduction/oxidation treatment on blue photorefraction in In:Fe:Cu:LiNbO3 crystals

In:Fe:Cu:LiNbO₃ crystals with reduced/oxidized treatments were prepared by the Czochralski method. The defect structure was analyzed by the UV‐Visible absorption spectra. The blue photorefractive properties, such as the refractive index change, response time, recording sensitivity, dynamic range as well as two‐wave coupling gain coefficient, were also investigated at 488 nm wavelength using the two‐wave coupling experiment. Comparing the as‐grown and oxidized In:Fe:Cu:LiNbO₃ crystals, the reduced sample has the highest recording sensitivity and largest dynamic range. Meanwhile, the high diffraction efficiency is still maintained. Experimental results definitely show that reduction treatment is an effective method to improve the blue photorefractive performance of In:Fe:Cu:LiNbO₃ crystals. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

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.     

Er：Yb：YCOB晶体制备及其激光二极管抽运激光特性

研究了Er：Yb：YCa4O(BO3)3(简称Er：Yb：YCOB)的多晶制备和单晶生长，用提拉法生长出光学质量优良的Er：Yb：YCOB单晶，测量了其吸收光谱和荧光光谱，分析了其能级和泵浦原理，并进行了以激光二极管为抽运源的激光试验，实现了Er：Yb：YCOB晶体的在1．55μn附近110mW的激光输出，且斜效率达18．9％。     

Computer simulation of superionic conductors: I. Anionic conductors: Review

The state of the art of the molecular dynamics simulation of superionic conductors is reviewed. The main studies devoted to the structural, dynamic, and transport properties of the basic classes of solid electrolytes with a conductivity via fluorine, chlorine, and oxygen anions are considered.