Zn:Fe:LiNbO3晶体全息存储性能

在ＬｉＮｂＯ３中掺进ＺｎＯ和Ｆｅ２Ｏ３生长了Ｚｎ：Ｆｅ：ＬｉＮｂＯ３晶体。     

Ce:Cu:SBN晶体的生长及其自泵浦位相共轭效应的研究

在铌酸锶钡中掺入ＣｅＯ２和ＣｕＯ，生长了Ｃｅ：Ｃｕ：ＳＢＮ晶体，测试了该晶体的衍射效率、自泵浦位相共轭反射率和响应时间。以Ｃｅ：Ｃｕ：ＳＢＮ晶体作为自泵浦位相共轭镜，以Ｚｎ：Ｆｅ：ＬｉＮｂＯ３晶体作为存储介质，实现了实时关联存储。     

Ce：Cu：SBN晶体的生长及其光折变效应的研究

简述了Ｃｅ：Ｃｕ：ＳＢＮ晶体的生长,测试了晶体的衍射效率、简并四波混频位相共轭反射率和响应时间,以Ｚｎ：Ｆｅ：ＬｉＮｂＯ３晶体作为存储介质,以Ｃｅ：Ｃｕ：ＳＢＮ晶体作为自泵浦位相共轭镜,实现了实时关联存储。     

双掺杂LiNbO3晶体的生长及其实时图象微分的研究

采用Ｃｚｏｃｈｒａｌｓｋｉ Ｚｎ：Ｆｅ：ＬｎＮｂＯ３晶体和Ｃｅ：Ｎｄ：ＬｉＮｂＯ３晶体。测试了晶体的抗光致散射能力、衍射效率和响应时间。以双掺杂ＬｉＮｂＯ３晶体作为全息记录材料,Ｃｅ：Ｃｕ：ＫＮＳＢＮ晶体构成自泵浦位相共轭镜,进行了实时图象边缘增强的研究,并探讨了不同的记录晶体对实验结果的影响。     

掺杂LiNbO3晶体压电性能与声表面波性能的研究

用拉拉法生长了多种掺杂ＬｉＮｂＯ３晶体,测定了压电性能和声表面波性能,结果表明,Ｓｒ：ＬｉＮｂＯ３和Ｔｉ：ＬｉＮｂＯ３较纯ＬｉＮｂＯ３晶体压电系数有较大增加,其他压电性能基本保持不变。首次发现其声表面波性能提高,尤其是延时温度系数明显降低,可见Ｓｒ：ＬｉＮｂＯ３和Ｔｉ：ＬｉｂＯ３晶体对制备质量声表面波器件具有重要意义。     

Eu：Fe：LiNbO3晶体双光束耦合异常现象的研究

在Ｅｕ：Ｆｅ：ＬｉＮｂＯ３晶体的双光束耦合实验中，减小晶体厚度，增大泵浦光束直径，都可使指数增益系数和衍射效率增大，２θ角度响应范围加宽。升高温度亦可增大衍射效率。本文对上述实验结果进行了理论分析。     

高能球磨法制备纳米晶Zn铁氧体

用高能球磨法制备了纳米晶Ｚｎ铁氧体。通过样品的Ｍｏｅｓｓｂａｕｅｒ谱及ＸＲＤ谱的测定,研究了纳米晶的形成过程。结果表明：球磨的３ｈα－Ｆｅ２Ｏ３即与ＺｎＯ发生机械化学反应生成Ｚｎ铁氧体,这种反应是通过先形成α－Ｆｅ２Ｏ３－ＺｎＯ固溶体而进行的。制得的纳米晶铁氧体有一定的晶格畸变。     

ZnxFe3—xO4的制备及性能

采用合适加剂在碱性溶液中制备了ＦｅＺｎ铁氧体，研究了其形成机理及磁性能，提出ＦｅＺｎ铁氧体的形成机理为：Ａｎ＾２＋＋２Ｆｅ＾３＋＋８０Ｈ＾－→ＺｎＦｅ２Ｏ４＋４Ｈ２Ｏ Ｆｅ＾２＋＋２Ｆｅ＾２＋＋８０Ｈ＾－→Ｆｅ３Ｏ４＋４Ｈ２Ｏ。     

一种制备r—Fe2O3薄膜的新方法

采用一种简单的新工艺分别在硅片和氧化铝陶瓷基片上制备了ｒ－Ｆｅ２Ｏ３薄膜。该工艺分３步完成：首先利用Ｆｅ（ＮＯ２）３酒精溶液通过浸渍涂布工艺制备ａ－Ｆｅ２Ｏ３薄膜，其次ａ－Ｆｅ２Ｏ３薄膜在氢气流中、３２０￣３５０℃之间热处理３０ｍｉｎ被还原为Ｆｅ３Ｏ４薄膜，最后Ｆｅ３Ｏ４薄膜在空气中２５０℃左右热处理３０ｍｉｎ被氧化为ｒ－Ｆｅ２Ｏ３薄膜。ＸＲＤ和ＳＥＭ分析结果表明该ｒ－Ｆｅ２Ｏ３薄膜呈尖晶石物相和     

不同热化学还原LiNbO_3：Ti或Mn晶体杂质电荷态和点缺陷

采用光学吸收和电子顺磁共振（ＥＳＲ）技术表征不同热化学还原ＬＩＮｂＯ３：Ｔｉ，Ｍｌｉ（ＬＮ：Ｔｉ，Ｍｎ）和纯的Ｌｉ／Ｎｂ＝０．９４５一致熔化ＬｉＮｂＯ３（ＬＮ）晶体的热力学还原习性．将ＬＮ：Ｔｉ（厚度为１ｍｍ）样品放在Ｌｉ２ＣＯ３中、６００℃、保温７ｈ，产生６９０ｕｒｎ（～１．８ｅＶ，Ｔ＝６７％）和峰值靠近７８５ｎｍ（Ｔ＝７１％）的７７０￣８１０ｎｍ光学吸收带，它们分别对应于Ｔｉ（３＋）的２Ｔ→２Ｅ跃迁以及室温稳定Ｆ＋心滞有一个电子的氧空位）．经真空１．２Ｐａ，８００℃２ｈ还原后，存在峰值为６７５ｎｍ（Ｔ＝５２％）的４８０～７８０ｎｍ平滑吸收带，它们是Ｔｉ（３＋）、Ｆ心和Ｆ＋心重叠吸收，但是，在Ａｒ气氛下、９００℃、８ｈ处理后，仅能看到峰值在６７５ｎｍ（Ｔ＝５２％）的６００～７８０ｎｍＴｉ（３＋）的弱吸收．来自未处理ＬＮ：Ｔｉ晶体的室温和Ｘ带的ＥＳＲ＄观察到ｇ＝４．３４８，共振磁场０．１５２ＴＨ（ｐ－ｐ）＝０．０１６３Ｔ微波吸收峰，以及四组精细结构Ｂ线（每一ｆｓ线是由６条超精细结构ｈｆｓ组成），ｇ值从３．４６０～１．６７９吸收，它们分别归为于晶体杂质Ｆｅ（３＋）和Ｍｎ（２＋）离子．真空还原后，Ｆｅ（３＋）的     

Phase Formation During Nonisothermal Decomposition of the Freeze-Dried Bi:Pb:Sr:Ba:Ca:Cu = 1.8:0.4:1.8:0.2:1.2:2.0 Complex Nitrate Powder

Nitrate powder with cation composition Bi:Pb:Sr:Ba:Ca:Cu = 1.8:0.4:1.8:0.2:1.2:2.0 was obtained by spray-frozen, freeze-drying technique. Samples of the nitrate precursor powder were placed in a heated furnace (heating rate 100°C/min) and extracted in air when temperature of the powdered samples attained values of 439, 495, 550, 600, 640, 647, 717, 766, 814, and 850°C. Samples have been investigated by X-ray diffraction analysis. The obtained data allow us to propose and discuss phase formation and decomposition processes and reactions that occur in non-isothermal conditions at different temperatures during thermal decomposition of the nitrate powder.     

Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: modeling of a single, long pulse length comparison

Two methods of producing the long pulse lengths that promote efficient extraction of energy from low-gain, quasi-four-level lasers are analyzed. A long pulse length output can mitigate laser-induced damage effects and can be generated in quasi-four-level lasers by two disparate methods. One method utilizes Q-switching techniques in resonators designed to extend the pulse length and another utilizes the first pulse in a relaxation oscillation pulse train. Models for quasi-four-level lasers are derived here taking into account the nonnegligible thermal population of the lower laser level. Closed-form expressions are derived for both modes of operation of quasi-four-level laser systems so the parametric dependencies of both forms of operation become obvious, allowing facile comparison. In addition, a combined absorption and quantum efficiency, germane for flash-lamp pumping, is calculated for both Cr and Er sensitizers. Although the former has the advantage of broad absorption bands, the latter has the advantage of a quantum efficiency approaching 3.     

Flash-lamp-pumped Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF lasers: experimental results of a single, long pulse length comparison

Flash-lamp-pumped, room-temperature Ho:Tm:Cr:YAG and Ho:Tm:Er:YLF are compared for single but long pulse operation, with pulse lengths of approximately 1.0 mus. Under similar operating conditions in normal-mode operation, a slope efficiency of 0.0331 was observed for Ho:Tm:Er:YLF compared with 0.0047 for Ho:Tm:Cr:YAG. For Q-switched operation, Ho:Tm:Er:YLF yielded a slope efficiency of 0.0075. In comparison, a slope efficiency of 0.0012 was obtained for Ho:Tm:Cr:YAG. Two methods of producing long pulse lengths are compared: pulse selection of normal-mode relaxation oscillations and Q-switching in a long resonator. Theoretical models developed in a companion paper for normal-mode relaxation oscillations and Q-switching in quasi-four-level solid-state lasers are in agreement with the experimental results.     

Electroluminescence of (Zn:Cd)S:Mn:Sm:Cl phosphors

The effect of field strength and frequency on electroluminescence brightness has been investigated for the binary systems (Zn:Cd)S:Mn:Cl and (Zn:Cd)S:Mn:Sm:Cl. The voltage dependence of the time averaged electroluminescent brightness shows the relation B = B_o exp ($\text{?}\text{C}\text{√}\text{v}$ and holds good over a wide range of frequencies, thus indicating that the mechanism of excitation is acceleration collision. The dependence of constants B_o and C on frequency of the applied field shows that the brightness of the electroluminescence is found to saturate at higher frequencies. It has been observed that EL peak emissions for these phosphors were found to be at 560 nm and 580 nm.     

Optical and EPR spectroscopy of Zn:Cr:ZnSe and Zn:Fe:ZnSe crystals

Optical and EPR characterization of Cr and Fe doped ZnSe crystals annealed in Zn vapor revealed a strong bleaching of the divalent state of transition metal ions. Photo induced EPR kinetics were studied in 20–80 K temperature range. Analysis of time-dependent data reveals Cr¹⁺ signal rise time decreases with increasing temperature. The non-exponential decay of Cr¹⁺ concentration were analyzed using Auger-type recombination process. The photoluminescence quantum yield of Cr²⁺ ions at ⁵E(D) → ⁵T₂(D) mid-IR transition excited via chromium ionization process was measured to be close to 100%.     

Growth of YLF:Yb:Tm:Nd for optical applications

The focus of this study is the behavior of Tm, Yb and Nd ions in the LiYF₄ (YLF) crystal. One YLF crystal was successfully grown by the Czochralski method; it was doped with 20 mol% Yb, 1.3 mol% Nd and 0.05 mol% Tm. The segregation coefficients of the dopants and lattice parameters were determined. The spectroscopic properties of samples with different amounts of Nd were obtained from absorption and emission studies.