共查询到19条相似文献,搜索用时 46 毫秒
1.
用气相输运平衡技术成功地制备出了近化学计量组分的Er∶LiNbO3晶体,系统 地研究了该 晶体的吸收边移动、可见—红外透射谱、荧光光谱的物理特性.与同成分Er∶LiNbO3 sub>晶体 相比, 近化学计量组分Er∶LiNbO3晶体的吸收边出现了“蓝移”;OH- sup>吸收带明显减弱 ;在可见—近红外波段呈现出更高的透过率;同时Er3+离子的发光强度也明显 提高. 这些结果表明近化学组分的Er∶LiNbO关键词:
近化学组分掺铒铌酸锂晶体
- 吸收带')" href="#">OH-吸收带
透射谱
荧光光谱 相似文献
2.
3.
利用气相平衡扩散法研制出掺镁不同组分的LiNbO3晶体,并对其极化特性进行了研究.研究表明晶体的开关电场和自发极化不仅与晶体组分[Li]/[Nb]比有关而且与掺镁量有关,[Li]/[Nb]比为0.973掺入2mol% MgO的近化学比LiNbO3晶体的开关电场仅为1.8kV/mm,是同成分晶体的1/12,且其极化结构的质量要远好于同成分LiNbO3晶体和近化学比LiNbO3晶体.
关键词:
气相平衡扩散
3晶体')" href="#">掺镁LiNbO3晶体
周期极化 相似文献
4.
本文报道了一组不同Li/Nb比和另一组不同掺Mg浓度的LiNbO3晶体室温OH-吸收带的实验结果,观察到OH-吸收带的三峰结构及其随Li/Nb比的变化,以及重掺Mg晶体中(6mol%MgO)OH-吸收带转变为双峰结构,并向高能端移动54cm-1。根据LiNbO3的晶体结构以及Abrahams和Smyth的缺陷结构模型,对化学计量晶体、一致熔化晶体和掺Mg晶体分别进行讨论。并提出重掺Mg晶体中OH-吸收带向高能端的移动可能是由于当掺Mg浓度超过阈值后Mg2+离子开始进入Nb位而引起的。
关键词: 相似文献
5.
6.
7.
我们通过测定MgO在同成分LiNbO3中的有效分凝系数、相位匹配温度与MgO浓度之间的关系,找到了使Mg:LiNbO3晶体的相位匹配温度达到最高的掺MgO配方,并克服了Mg:LiNbO3晶体在高掺杂生长时易出现生长条纹和脱溶等问题,从而生长出了抗光折变能力强,光学均匀性良好的Mg:LiNbO3晶体。用于连续泵浦Nd:YAG声-光调Q腔内倍频时,获得了平均功率最高达2瓦的二次谐波输出。
关键词: 相似文献
8.
9.
本文用X射线衍射、热处理及差热分析等方法测定了SrNb2O6-NaNbO3-LiNbO3赝三元系的室温截面及相应的SrNb2O6-NaNbO3,SrNb2O6-LiNbO3和NaNbO3-LiNbO3等三个赝二元系相图;粗略地研究了Sr0.42Na0.16NbO3-LiNbO3系的纵截面;含5mol%LiNbO3及10mol%LiNbO3的SrNb2O6-NaNbO3的纵截面。确定了室温Sr2Na(NbO3)5(以下略为S2N)相为四方钨青铜结构。其点阵常数为a=12.36?,c=3.906?.LiNbO3在S2N相内的溶解度可达~10mol%,当LiNbO3含量超过5mol%时,S2N相畸变为S2N′相。S2N′相为正交晶系。实验确定室温S2N(S2N′)相系亚稳相。在900-1100℃长时间退火即分解为SrNb2O6和以NaNbO3为基的固溶体的混合物。
关键词: 相似文献
10.
11.
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
12.
The near stoichiometric LiNbO3 crystals co-doped with ZrO2 and Fe2O3 have been grown from a Li-rich melt (Li/Nb=1.38, atomic ratio) by the Czochralski method in air atmosphere at the first time. The OH? absorption and UV–vis absorption spectra were characterized to investigate the defect structure of the crystals. The appearances of the 3479 cm?1 absorption peak and 358 nm absorption edge manifest that the composition of the grown crystal is close to the stoichiometric ratio. The blue holographic properties were also measured by the two-wave coupling experiments. As a result, in the near stoichiometric Zr:Fe:LiNbO3 crystals, photorefractive response speed, recording sensitivity, and two-wave coupling gain coefficient are significantly enhanced. Meanwhile, the high saturation diffraction efficiency is still maintained. These findings prove that the material of near stoichiometric Zr:Fe:LiNbO3 crystals are a promising candidate for blue photorefractive holographic recording. 相似文献
13.
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
14.
15.
N. V. Sidorov M. N. Palatnikov N. A. Teplyakova A. A. Gabain I. N. Efremov 《Optics and Spectroscopy》2016,120(4):633-638
Using the electronic spectroscopy method, the laser-conoscopy method, and the Raman light-scattering method, we have studied the structural homogeneity of LiNbO3 crystals doped with 0.03–4.5 mol % of ZnO. We have found that, as the laser radiation power is increased to 90 mW, the conoscopic patterns of crystals show additional distortions, which are attributed to the manifestation of the photorefractive effect. For the LiNbO3 crystal doped with 4.5 mol % of ZnO, in which the photorefractive effect is low, we have revealed a considerable shift (compared to the remaining crystals) of the optical absorption edge toward the shortwavelength range, which indicates a high structural homogeneity of this crystal. We have shown that, in the LiNbO3 crystal doped by 0.05 mol % ZnO, due to the displacement of NbLi and Li□ structural defects by Zn2+ cations, the crystal structure is ordered and, simultaneously, the number of defects with localized electrons decreases. 相似文献
16.
We studied the visible and IR dispersion of absorption coefficient and refractive index for congruent LiNbO3 and Mg:LiNbO3 crystals before and after chemical reduction at different annealing temperatures. The concentration of Mg in Mg:LiNbO3 samples was just below or above the photorefractive threshold. The reduction-induced changes in the absorption coefficient reveal the formation of polarons typical for doped LiNbO3 crystals. It was shown that the polaron concentration is maximal when the Mg concentration is just below the photorefractive threshold and the annealing temperature is near 500 °C. This temperature is optimal for the most efficient polaron formation at all considered concentrations of Mg. The fitting of the experimental absorption dispersion curves indicates that intermediate polarons are formed in LiNbO3:Mg crystals preferably. The spectral dependence of transmission for samples of lithium niobate of various thicknesses was studied. The results indicate that there are spatial regions with much greater absorption than that of bulk crystals. We assume that, in general, polarons are localized in thin near-surface regions. The spectral dependence of the refractive index in the vicinity of the phonon absorption edge indicates some essential changes of the phonon subsystem taking place after reduction. The infrared contribution into the dispersion of the dielectric function real part increases considerably after reduction. PACS 71.38.Ht; 71.38.-k; 78.20.Ci 相似文献
17.
I. Baumann F. Cusso B. Herreros H. Holzbrecher H. Paulus K. Schäfer W. Sohler 《Applied Physics A: Materials Science & Processing》1999,68(3):321-324
3 by diffusion doping is investigated by means of secondary neutral mass spectrometry and secondary ion mass spectrometry.
The diffusion of praseodymium in LiNbO3 can be described by Fick’s laws of diffusion with a concentration-independent diffusion coefficient and a limited solubility
of praseodymium in LiNbO3 increasing exponentially with rising temperature. The diffusion depends on the Li2O content of the LiNbO3 crystal. For LiNbO3 crystals with a nominal slight difference in the congruent composition, the diffusion constants and activation energies for
Z-cut LiNbO3 are 3.28×10-5 cm2/s and 2.27 eV, and 1.39×10-5 cm2/s and 2.24 eV, respectively. Titanium-doped waveguides are formed in Pr:LiNbO3 and characterised in relation to waveguide loss and absorption in the visible and near infrared.
Received: 17 September 1998 / Accepted: 11 November 1998 相似文献
18.
T. Volk M. Wöhlecke N. Rubinina N. V. Razumovski F. Jermann C. Fischer R. Böwer 《Applied Physics A: Materials Science & Processing》1995,60(2):217-225
We report on a detailed investigation (EPR, SHG, optical absorption, luminescence and Raman scattering) on the new damage-resistant impurity indium in LiNbO3, where the increased photoconductivity strongly reduces the photorefractive effect. EPR and optical absorption measurements point to a complete disappearance of the Nb antisite in LiNbO3: In for all In concentrations. We believe that the very effective driving out of Nb antisites by In is due to the trivalent charge state of In and the possibility of charge self-compensation. Similarities in the properties of Mg-, Zn- or Indoped samples are discussed. Simultaneous doping with In and Zn leads to an addition of both contributions, in particular for optical frequency doubling and luminescence. Raman studies prove that In does not improve the stoichiometry of the crystals. Indium doping provides the possibility to control simultaneously phase-matching conditions and to reduce drastically photorefraction. Therefore, In co-doped LiNbO3 compositions are promising materials for applications after solving contemporary growth problems. 相似文献
19.
Xiaochun Li Hongde Liu Jingjun Xu Ling Zhang Shiguo Liu 《Solid State Communications》2007,141(3):113-116
The ultraviolet absorption edges of LiNbO3 crystals with different Li2O contents and MgO doping concentrations were investigated. The generally defined absorption edges at absorption coefficient α=15 or 20 cm−1 of all these crystals fit the Urbach rule perfectly. The origin of this absorption edges in non-stoichiometric LiNbO3 crystals is attributed to the presence of Li vacancies. 相似文献