共查询到20条相似文献,搜索用时 109 毫秒
1.
中国科学院物理研究所超声压电材料组 《物理》1974,(1)
浮力提垃单晶炉是利用浮力的原理来提拉单晶的新型单晶炉.它结构简单,振动小,造价低廉.提拉速率范围为0.5毫米~150毫米/小时,连续可调,在长时间提拉中,拉速不稳定度<5%.通过二年多来的试用,性能稳定可靠.已先后拉出较大块的铌酸锂单晶和锗酸铋单晶. 相似文献
2.
3.
选用多种切型铌酸锂(LiNbO_3)单晶,研究了铁基非晶合金(Metglas)/LiNbO_3叠层复合材料基于伸缩-剪切模式的磁电耦合性能,揭示了铌酸锂单晶压电系数与复合材料剪切磁电耦合系数的对应关系,在使用铌酸锂xzt/30~?切型时得到了最优化剪切磁电系数.通过SrFe12O19薄磁带提供偏置磁场,Metglas/LiNbO_3磁电复合材料可在没有外加直流磁场时实现剪切磁电响应,并在0.991 MHz和3.51 MHz频率时分别测出了谐振磁电系数,有望将铌酸锂基剪切磁电复合材料用于高频磁场探测. 相似文献
4.
《物理学报》2017,(6)
通过弹性力学方法计算了基于厚度剪切模式的铌酸锂(LiNbO_3)基磁电复合材料磁电系数与铌酸锂晶体切型、磁致伸缩材料种类、材料尺寸的关系,并讨论了两种不同复合结构边界条件对剪切磁电性能的影响.计算结果表明:(xzt)30°切型铌酸锂单晶具有最大剪切压电系数dp15,制作成的复合材料具有最大剪切磁电系数αE15;通过两相尺寸优化,伸缩-剪切模式Terfenol-D/LiNbO_3复合材料最大剪切磁电系数为24.13 V/(cm·Oe),剪切-剪切模式Metglas/LiNbO_3复合材料最大剪切磁电系数为11.46V/(cm·Oe).实验结果与理论计算规律相符,研究结果为剪切磁电复合结构的设计、剪切模式铌酸锂切型的选择优化提供了指导,有望利用高机械品质因数Q_m值的铌酸锂单晶设计高频谐振磁场探测器. 相似文献
5.
6.
7.
8.
铌酸锂,作为应用最广泛的非线性光学晶体之一,近十年来由于薄膜铌酸锂晶圆的出现而再次获得了学术界与产业界的关注.基于薄膜铌酸锂的集成光电子器件的优越性能已在诸多应用中得到演示,例如光信息处理、激光雷达、光学频率梳、微波光子学和量子光学等. 2020年,薄膜铌酸锂器件通过光刻技术在6 in(1 in=2.54 cm)晶圆上的成功制备,推动了铌酸锂加工从实验室逐步走向工业化.薄膜铌酸锂光子器件的研究主要聚焦于利用电光、声光和二阶/三阶非线性效应进行光调制或频率转换;最近三年,掺杂稀土离子还成功赋予铌酸锂增益特性,实现了片上铌酸锂放大器和激光器.本文将简略回顾薄膜铌酸锂的发展过程,着眼于集成光子器件,介绍国内外研究组取得的进展、意义以及面临的挑战. 相似文献
9.
10.
11.
Ferroelectric domain inversion in near-stoichiometric lithium niobate for high efficiency blue light generation 总被引:2,自引:0,他引:2
Y.-L. Chen J.-J. Xu X.-Z. Zhang Y.-F. Kong X.-J. Chen G.-Y. Zhang 《Applied Physics A: Materials Science & Processing》2002,74(2):187-190
LiNbO3 single crystals with a composition close to stoichiometry ([Li]/[Li+Nb]=0.496), 16 mm in diameter and 40 mm in length were
grown by the Czochralski method using K2O flux. The domain reversal characteristics of near-stoichiometric LiNbO3 single crystals were investigated. The switching field required for 180° ferroelectric domain reversal in the near-stoichiometric
crystal at room temperature was 7.5 KV/mm. This is about one third of the switching field required for conventional LiNbO3 crystals. Domain reversal (180°) in near-stoichiometric LiNbO3 samples of 1.0 mm thickness has been achieved. Samples have been evaluated by second harmonic generation and conversion efficiencies
of up to 32% have been obtained.
Received: 8 November 2000 / Accepted: 29 January 2001 / Published online: 20 June 2001 相似文献
12.
Congruently grown LiNbO3 single crystals show both high oxygen and lithium ion conductivity at temperatures above 500 °C. The high oxygen ion conductivity
can be understood in terms of a certain amount of oxygen vacancies already present in congruently grown LiNbO3 single crystals. Thermal treatment of LiNbO3 produces additional oxygen vacancies. The absorption bands introduced by this procedure are investigated. It is found that
the electrons which are generated during the reduction process are homogeneously distributed among all oxygen vacancies in
the LiNbO3 single crystals. The electrocoloration phenomenon in LiNbO3 single crystals is due to the process of injection of lithium ions and electrons into LiNbO3 by a double charge mechanism. Investigations of the optical and electrical properties of electrocolored LiNbO3 crystals are reported. It is shown that the absorption spectra of thermally and electrochemically reduced samples are identical
and that the origin of the absorption processes has to be therefore the same in both cases. That means, additional electrons
produced by the double charge injection of lithium ions and electrons are also homogeneously distributed among the oxygen
vacancies. This supports our hypothesis that a certain amount of oxygen vacancies has to be present already in as-grown LiNbO3 single crystals. 相似文献
13.
Doping MgO, MnO and Fe2O3 in LiNbO3 crystals, tri-doped Mg:Mn:Fe:LiNbO3 single crystals were prepared by the conventional Czochralski method. The UV-vis absorption spectra were measured and the shift mechanism of absorption edge was also investigated in this paper. In Mg:Mn:Fe:LiNbO3 crystal, Mn and Fe locate at the deep level and the shallow level, respectively. The two-photon holographic storage is realized in Mg:Mn:Fe:LiNbO3 crystals by using He-Ne laser as the light source and ultraviolet as the gating light. The results indicated that the recording time can be significantly reduced for introducing Mg2+ in the Mg:Mn:Fe:LiNbO3 crystal. 相似文献
14.
O. Jarolímek 《Czechoslovak Journal of Physics》1995,45(3):263-273
Conditions for the growth of LiNbO3:MgO single crystals by the Czochralski method were optimized. An upper limit of the molar MgO concentration in the melt for obtaining limpid, optically homogeneous crystals was determined. The Curie temperature was measured on precisely defined samples and so real MgO contents in the single crystal phase, distribution coefficients and longitudinal concentration profiles could be determined using this calibration curve. X-ray diffraction and optical absorption in the near infra-red and in the ultra-violet and visible regions were also studied on LiNbO3:MgO single crystals. Lattice constants and positions of the OH– absorption band and of the short-wave absorption edge were determined on the basis of described measurements. Dependences of all the above-mentioned properties on the molar MgO concentration were found out. The simple model of microscopic mechanisms for explaining these experimental data was proposed. 相似文献
15.
Xiangli Liu 《Optik》2014
Congruent Zn(7 mol%):Ce:Cu:LiNbO3 single crystal was grown by the Czochralski method in air. The occupation mechanism of the Zn2+ was discussed by an infrared transmittance spectrum. The nonvolatile holographic recording in Zn(7 mol%):Ce:Cu:LiNbO3 single crystal was measured by two-photon fixed method. Zn(7 mol%):Ce:Cu:LiNbO3 single crystals present the faster recording time and higher light-induced scattering resistance ability comparing with Ce:Cu:LiNbO3 single crystals. 相似文献
16.
A series of LiNbO3 crystals doped with various concentrations of ZnO and fixed concentrations of RuO2 and Fe2O3 have been grown by the Czochralski method from the congruent melts. The type of charge carriers was determined by Kr+ laser (476 nm) and He–Ne laser (633 nm). The results revealed that the holes were the dominant charge carriers at blue light irradiation. Dual-wavelength and two-color techniques were employed to investigate the nonvolatile holographic storage properties of Ru:Fe:LiNbO3 and Zn doped Ru:Fe:LiNbO3 crystals. The essential parameters of blue nonvolatile holographic storage in Zn:Ru:Fe:LiNbO3 crystals were enhanced greatly with the increase of Zn concentration. This indicates that the damage resistant dopants Zn2+ ions enhance the photorefractive properties at 476 nm wavelength instead of suppressing the photorefraction. The different mechanisms of blue photorefractive and nonvolatile holographic storage properties by dual wavelength recording in Zn:Ru:Fe:LiNbO3 crystals were discussed. 相似文献
17.
Zuo Xiaoxi 《Optik》2005,116(7):361-364
Fe:LiNbO3 and In:Fe:LiNbO3 crystals were grown by Czochralski method. The absorption spectra were measured to investigate their defect structure. The photo damage resistance and photorefractive properties were measured. The photo damage resistance of the In:Fe:LiNbO3 crystal in which the In concentration is above the threshold value is one order of magnitude higher than that of the Fe:LiNbO3 crystal. The mechanisms of the violet shift of the absorption edge and the enhancement of the photorefractive effect of In:Fe:LiNbO3 crystals were investigated. 相似文献
18.
N. V. Sidorov M. N. Palatnikov A. A. Yanichev A. A. Gabain O. Yu. Pikoul A. N. Smirnov 《Optics and Spectroscopy》2013,115(4):523-529
Photorefractive properties and structural and optical homogeneity of (1) LiNbO3:Cu crystals ([Cu] = 0.015 mas %) grown from a congruent melt, (2) nominally pure stoichiometric crystals grown from a melt with 58.6 mol % of Li2O (LiNbO3stoich), and (3) nominally pure congruent crystals (LiNbO3congr) have been studied using the Raman-spectroscopy method with excitation in the UV, visible, and near-IR ranges; the laser-conoscopy method; and the electron paramagnetic resonance-spectroscopy method. In optically uniaxial LiNbO3 crystals, a weak optical biaxiality has been revealed, which is attributed to an insignificant deformation of the optical indicatrix. This deformation can be caused both by the initial structural inhomogeneity of crystals and by the photorefractive effect. It has been shown that, under the action of light, charge exchange of copper cations Cu2+ → Cu+ takes place in the crystal LiNbO3:Cu ([Cu] = 0.015 mas %). The LiNbO3:Cu crystal exhibits photorefractive properties not only because of the occurrence of intrinsic defects with electrons localized at them, as is the case with the LiNbO3stoich and LiNbO3congr crystals, but also due to the charge exchange of copper cations under the action of the laser radiation. 相似文献
19.
A series of Mg:Ce:Cu:LiNbO3 crystals has been grown by Czochralski method. Their infrared transmittance spectra and ultraviolet-visible absorption spectra were measured and discussed to investigate their defect structure. The nonvolatile holographic recording of Mg:Ce:Cu:LiNbO3 crystals was characterized by the two-photon fixed method. We found that the recording time of Mg:Ce:Cu:LiNbO3 crystals became shorter and nonvolatile diffraction efficiency decreases with the increase of Mg doping concentration, especially doping with Mg approaches and exceeds the so-called threshold. And the nonvolatility vanishes when the concentration of MgO exceeds 4 mol%. The intrinsic and extrinsic defects were discussed to explain the nonvolatile holographic properties in the Mg:Ce:Cu:LiNbO3 crystals. 相似文献
20.
K. A. Kuznetsov S. P. Kovalev G. K. Kitaeva T. D. Wang Y. Y. Lin Y. C. Huang I. I. Naumova A. N. Penin 《Applied physics. B, Lasers and optics》2010,101(4):811-815
We study dispersion of the dielectric function real part ε′ in the terahertz-frequency range for bulk and periodically poled congruent LiNbO3 and Mg:LiNbO3 crystals. The concentration of Mg in Mg:LiNbO3 samples was close to 5 mol%, which is the photorefractive threshold. Approximate expressions for extraordinary polariton dispersion dependence were obtained in the range 0.5–6.5 THz. The influence of Mg-dopant on the optical properties of crystals in the terahertz range is revealed. Changes of the defect structure of lithium niobate crystals are discussed. 相似文献