Mg：Er：LiNbO3晶体的激光性能和550nm寿命特性研究

为了测试Mg∶Er∶LiNbO3晶体的光损伤阈值和红外光谱,采用Czochralski技术生长出优质的Mgx∶Ery∶LiNbO3(x=0.02,0.04,0.06,0.08,y=0.01(摩尔分数))晶体。通过实验得出Mg(0.06)∶Er∶LiNbO3和Mg(0.08)∶Er∶LiNbO3晶体抗光损伤阈值比LiNbO3晶体提高2个数量级以上,且它们的红外光谱OH-吸收峰移到3535cm-1附近;在波长510nm^580nm范围内得到Mg∶Er∶LiNbO3晶体稳态发射谱。结果表明,Mg2+浓度增加抗光损伤能力增加,掺进摩尔分数为0.04的MgO是Mg∶Er∶LiNbO3晶体寿命最长的晶体。

微量稀土Er对Al-5Mg合金组织与性能的影响

采用铸锭冶金法,制备含不同量稀土元素Er的Al-5Mg合金。利用拉伸力学性能测试、OM、XRD、SEM、TEM及EDS分析等分析测试手段,研究微量Er对Al-5Mg合金微观组织与力学性能的影响。结果表明:Er可以明显提高Al-5Mg合金的强度,添加0.4%Er(质量分数)的Al-5Mg合金的冷轧态屈服强度(σ0.2)提高了81MPa,而延伸率变化不大;Er的加入还能减少Al-5Mg合金的枝晶偏析,并可显著细化合金的晶粒组织;Er对晶粒的细化机理与其添加量有关,当Er含量较低时,符合传统的稀土细化机理;当Er含量较高时,由于在熔体中形成了初生Al3Er质点,在结晶形核时可以作为非均质形核核心,从而可显著细化晶粒组织;Er对合金的强化效应主要来自于晶粒细化及在晶内形成的细小二次Al3Er质点。根据实验结果可知,添加0.4%Er可使合金具有较为优异的综合性能。

Mg:In:Er:LiNbO_3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。

Li^+,Zn^(2+),Mg^(2+)掺杂Lu_2O_3∶Er^(3+)荧光粉的制备及发光特性

用微波高温固相法合成了Er^(3+)单掺Lu_2O_3,Li^+与Er^(3+)共掺Lu_2O_3及Li^+,Zn^(2+),Mg^(2+)掺杂Lu_2O_3∶Er^(3+)的荧光粉。实验表明金属离子Li^+、Zn^(2+)、Mg^(2+)、Er^(3+)掺杂Lu_2O_3,不影响Lu_2O_3的立方晶相。扫描电子显微镜测量表明,Li^+掺杂可以有效改善粉体的分散性和形貌,Li^+,Zn^(2+),Mg^(2+)共掺杂获得的粉体颗粒分布更加均匀,粒径范围为80～100 nm。379 nm激发下,Li^+与Er^(3+)共掺样品发光较单掺Er^(3+)样品在565 nm处的发光增强了4.5倍,而Li^+、Zn^(2+)、Mg^(2+)与Er^(3+)共掺样品较其发光增强5.3倍。980 nm激发下,Li^+与Er^(3+)共掺样品,Li^+、Zn^(2+)、Mg^(2+)与Er^(3+)共掺样品的发光分别比单掺Er^(3+)样品在565 nm处发光增强23倍与39倍,在662 nm处发光强度分别增强20倍与43倍。379 nm激发下,较单掺Er^(3+)的样品,掺杂Li^+的样品和Li^+,Zn^(2+),Mg^(2+)和Er^(3+)共掺的样品荧光寿命均有所增加,而Zn^(2+)、Er^(3+)共掺及Mg^(2+)、Er^(3+)共掺样品的荧光寿命则有所缩短。

Mg：Zn：LiNbO3晶体光损伤和倍频性能的研究

以Czochralski技术生长Mg(3%)∶Zn∶(x%)∶LiNbO3(x=1,2,3)(摩尔分数)。测试晶体光损伤阈值,Mg(3%)∶Zn(3%)∶LiNbO3晶体光损伤阈值比LiNbO3晶体提高了2个数量级以上。测试晶体红外光谱Mg(3%)∶Zn(3%)∶LiNbO3晶体OH-吸收峰位置由LiNbO3的3 482 cm-1移到3 532 cm-1,即晶体掺杂达到阈值浓度。采用角度匹配,测试晶体的倍频转换效率。激光功率密度很高时,晶体出现暗迹,倍频转换效率下降,暗迹是由倍频光引起,与基频光无关。氧化的晶体可以减弱暗迹。对晶体光损伤阈值的增强,OH-吸收峰的移动,暗迹产生的机理进行阐述和研究。

Mg^(2+)掺杂对上转换发光材料Na_(2)Zn_(3)Si_(2)O_(8):Er^(3+)发光性能的影响

采用高温固相法成功合成了新型Mg^(2+)掺杂Na_(2)Zn_(3)Si_(2)O_(8):Er^(3+)荧光粉,研究了其物相结构、上转换发光特性以及热稳定性和单色性。研究结果表明,Mg^(2+)离子的掺杂对Na_(2)Zn_(3)Si_(2)O_(8):Er^(3+)晶体结构没有影响,并且在980 nm激发下出现了Er^(3+)离子的绿色和红色特征发射带,Mg^(2+)离子的掺入使Er^(3+)离子在661 nm处的红色发射强度提高了16倍,这归因于随着掺杂Mg^(2+)离子CO32-基团和OH-基团数量的逐渐减少,无辐射跃迁几率减少,最终导致发光强度的增强。通过热稳定性研究发现,Na_(2)Zn_(3)Si_(2)O_(8):3%Er^(3+)、1%Mg^(2+)在25℃~250℃温度范围内表现出较好的热稳定性,并随着温度的升高样品呈橙红色发光。优化后的样品在固态照明领域有潜在应用价值。

掺Er^(3+)离子Mg-Al尖晶石晶体光谱性质分析

实验给出了掺Er3+ ∶Mg Al尖晶石晶体的吸收谱、荧光谱和激发谱 ,确定了Er3+ 离子在Mg Al尖晶石晶体中的能级位置。用Judd Ofelt理论计算得到了掺Er3+ ∶Mg Al尖晶石晶体的光谱特性参数。最后对该掺杂晶体出光的可能性进行了分析。

Shape controllable synthesis and enhanced upconversion photoluminescence ofβ-NaGdF4:Yb^3+,Er^3+nanocrystals by introducing Mg(^2+)

Different concentrations of Mg^（2＋） -doped hexagonal phase NaGdF_4：Yb^（3＋）, Er^（3＋）nanocrystals（NCs） were synthesized by a modified solvothermal method. Successful codoping of Mg^（2＋）ions in upconversion nanoparticles（UCNPs） was supported by XRD, SEM, EDS, and PL analyses. The effects of Mg^（2＋）doping on the morphology and the intensity of the upconversion（UC） emission were discussed in detail. It turned out that with the concentration of Mg^（2＋）increasing, the morphology of the nanoparticles turn to change gradually and the UC emission was increasing gradually as well. Notably the UC fluorescence intensities of Er^（3＋）were gradually improved owing to the codoped Mg^（2＋）and then achieved a maximum level as the concentration of Mg^（2＋）ions was 60 mol% from the amendment of the crystal structure of β-NaGdF_4：Yb^（3＋）,Er^（3＋）nanoparticles. Moreover, the UC luminescence properties of the rare-earth（Yb3＋, Er^（3＋）） ions codoped NaGdF_4 nanocrystals were investigated in detail under 980-nm excitation.

OH^- absorption and nonvolatile holographic storage properties in Mg:Ru:Fe:LiNbO_3 crystal as a function of Mg concentration

Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.

Influence of Oxidation and Reduction Treatments on the Photorefractive Properties of Mg:In:Fe:LiNbO_3 Crystals

A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distortion method, and their response time and exponential gain coefficient were tested by two-beam coupling experiment. Besides, the effective carrier concentration has been calculated. The results showed that the absorption edges of reduced and oxidized crystals are respectively shifted to violet and Einstein compared with those of the growth state crystal. From oxidation state to growth state to reduction state of the samples, the photo scattering resistance ability and response time decrease while the exponential gain coefficient and concentration of effective carriers increase. The reduction treatment was necessary for the Mg：In：Fe：LiNbO3 crystals to enhance their photorefractive properties.

Optical Property of LiNbO_3 Crystal Codoped with In, Mg and Fe

In 2O 3, MgO and Fe 2O 3 were doped in LiNbO3 and Czochralski method was used to grow In:Mg:Fe:LiNbO 3 crystals. The OH - extension transmission spectra, light scattering resistance ability, two wave coupled diffraction efficiency and response time of the crystal were measured. Codoping In and Mg in crystal will improve its light scattering resistance ability and response time. Doping In can increase the ability to replace antisite Nb and decrease the doping quantity of Mg. All these are propitious to improve the optical homogeneity of crystal. Doping Fe can improve the photorefractive sensitivity for LiNbO 3 crystal. We discussed the site of In, Mg and Fe in LiNbO 3 crystals and the influence of the absorption peak of OH - transmission spectra on photorefractive property for LiNbO 3 crystal.

The Effect of Oxidation/Reduction Disposing on Optical Properties of Mg:Fe:Mn:LiNbO_3 Crystals

The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. Compared with As-grown Mg:Mn:Fe:LiNbO 3, the absorption edge in UV-Vis. absorption spectrum of the oxidized sample and the reduced shifts to the violet and the red, respectively. Reduction increases the absorption of crystals in visible light region. In two-wave coupling experiments, the writing time, maximum diffraction efficiency and the erasure time of crystal samples in the same conditions are determined. The results indicate that oxidation and reduction disposing has great effect on the holographic recording properties of these crystals. The reduced crystal exhibits the fastest response time of 160 s among the crystal series. The mechanism of post-disposing effect on the holographic recording properties of Mg:Mn:Fe:LiNbO 3 crystals are investigated.

Mg∶Fe∶LiNbO_3晶体的生长及光学性能研究

在Fe∶LiNbO3中掺进MgO和Fe2 O3以提拉技术生长Mg∶Fe∶LiNbO3晶体 对晶体进行极化和还原处理 测试晶体的吸收光谱 ,Mg∶Fe∶LiNbO3晶体吸收边相对Fe∶LiNbO3晶体发生紫移 测试晶体的红外光谱 ,Mg∶(5mol % )Fe∶LiNbO3晶体OH 吸收峰由Fe∶LiNbO3晶体的 3482cm- 1移到35 34cm- 1 采用锂空位模型阐述Mg∶Fe∶LiNbO3晶体 ,吸收边和OH- 吸收峰移动的机理 测试晶体的抗光致散射能力 Mg∶(5mol% )Fe∶LiNbO3晶体抗光致散射能力比Fe∶LiNbO3晶体提高一个数量级以上 测试晶体的衍射效率和响应时间

高浓度掺Er^(3+)铌酸锂晶体的光谱参数计算

用提拉法成功地生长了6mol%的高浓度掺铒铌酸锂晶体。测量了晶体的两个非偏振方向(X和Z)以及两个偏振方向(π和δ)的吸收光谱。高浓度掺铒铌酸锂晶体的吸收系数高,有利于提高泵浦效率。根据所测的吸收光谱用Judd-Ofelt理论拟合出了Er3+离子的强度参数Ωλ。所得的均方差结果显示偏振拟合的误差要小于非偏振拟合。利用偏振吸收数据计算了各能级跃迁的自发辐射跃迁几率(AJJ′)、辐射寿命(τ)、荧光分支比(β)和积分发射截面(σp)等参数,对计算结果进行了讨论并与其他文献的报道结果进行了比较。

Mg^(2+)对Fe∶LiNbO_3晶体光折变响应时间的影响

在 Fe∶Li Nb O3 中掺进 3 mol%和 6mol% Mg O,生长了 Mg∶Fe∶L i Nb O3 晶体 .测试了 Mg∶Fe∶Li Nb O3 晶体抗光致散射能力、衍射效率、响应时间和光电导 .推导响应时间与光电导之间的关系 .在 Fe∶Li Nb O3 晶体中掺进 6mol%的 Mg2 + ,它的抗光致散射能力比Fe∶L i Nb O3 晶体提高一个数量级 ,响应速度比 Fe∶Li Nb O3

Mg:Ce:Fe:LiNbO_3晶体生长及其全息存储性能

在同成分LiNbO3(LN)中,掺入MgO的摩尔分数分别为0,2%,4%,6%,掺入(质量分数)0.1%CeO2和0.08%Fe2O3,采用提拉法生长了优质的Mg:Ce:Fe:LN晶体。检测了Mg:Ce:Fe:LN晶体的红外透射光谱和光损伤阈值。结果表明:6%Mg:0.1%Ce:0.08%Fe:LN晶体的OH-振动吸收峰紫移到3532cm-1,其光损伤阈值比Ce:Fe:LN晶体提高2个数量级以上。用二波耦合光路测试晶体的衍射效率,写入时间和擦除时间。计算了光折变灵敏度和动态范围。结果表明:Mg:Ce:Fe:LN晶体全息存储性能优于Fe:LN晶体和Ce:Fe:LN晶体。以4%Mg:0.1%Ce:0.08%Fe:LN晶体作为全息记录材料,实现了总存储页面为3200幅图像的存储,再现图像清晰完整。

2.94μm Er:YAG电光调Q激光器及应用研究

随着2.94μm激光在医学中的应用日益广泛,控制工作激光参数提高医疗安全性能显得尤为重要,对工作的激光进行调Q是很有必要的。介绍了利用双布儒斯特角切割的LiNbO_3晶体作为电光Q开关的Er:YAG调Q激光器,在工作频率5 Hz,脉冲泵浦能量92 J条件下,获得了脉宽103～110 ns,能量达到87 mJ的调Q脉冲激光输出。并分别在静态和调Q模式下对龋牙进行了窝洞制样,利用扫描电子显微镜对样本扫描,对比显示调Q激光制样的效果更好。

Mg:Nd:LiNbO_3晶体倍频性能的研究

以Czochralski技术首次系统生长Mg:Nd:LiNbO3晶体。测试晶体的荧光光谱,(1.0%,3.0%,5.0%,6.5%,8%)(摩尔分数,下同)Mg:Nd:LiNbO3晶体在0.888μm,1.088μm和2.171μm有最强的谱线。测试晶体抗光损伤能力,x(MgO)浓度高于5%的Mg:Nd:LiNbO3晶体抗光损伤能力比Nd:LiNbO3晶体提高2个数量级以上。Mg:Nd:LiNbO3晶体相位匹配温度随掺进MgO的浓度而改变,x(MgO)=5%时达到最大值,MgO浓度继续增加相位匹配温度下降。Mg(8%):Nd:LiNbO3晶体相位匹配温度接近室温。Mg(6.5%):Nd:LiNbO3中Mg2+的分凝系数接近于1,它有最高的倍频转换效率η=32.3%。

Mg:Fe:LiNbO_3晶体光学性能的研究

在LiNbO3中掺杂光折变敏感杂质离子Fe2+/Fe3+和抗光致散射杂质离子Mg2+,以提拉法生长Mg∶Fe∶LiNbO3晶体。测试晶体吸收光谱、红外光谱。Mg∶Fe∶LiNbO3晶体的吸收边相对Fe∶LiNbO3晶体发生紫移。当Mg2+浓度达到阈值浓度,Mg(6%)∶Fe∶LiNbO3晶体OH-吸收峰由3482cm-1移到3529cm-1。测试晶体的位相共轭反射率和响应时间,计算光电导。Mg(6%)∶Fe∶LiNbO3晶体的响应速度和光电导比Fe∶LiNbO3晶体有较大提高。

Zn∶Mg∶LiNbO_3抗光折变性能机理的研究

LiNbO 3crystal possesses electro optic effect and nonlinear optical effect.Bec ars e it is easy to generate photo damage(photorefractive) for LiNbO 3.This limits i ts application in some fields.When doping 6mol% ZnO or 5mol% MgO in LiNbO 3 cry stal to grow Zn∶LiNbO 3 or Mg∶LiNbO 3 crystal,the photo damage resistance ab ility fo these two crystals is two orders of magnitude higher than that of LiNbO 3.We doped 3mol% ZnO and 3mol% MgO to grow Zn∶Mg∶LiNbO 3 crystal and used Fourier spectrophotometer to measure the infrared transmission spectra.The waven umber range to measure the OH - stretched vibration transmission spectra of Zn ∶LiNbO 3,Mg∶LiNbO 3 and Zn∶Mg∶LiNbO 3 crystal is 3200 4000cm -1 .The measurement result is that the OH - stretched vibration absorption peak of Zn( 6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 crystal is at 3535cm -1 (2.83μm),while that of pure LiNbO 3,Zn(3mol%):LiNbO 3 and M g(3mol%):LiNbO 3 is at 3484cm -1 (2.87μm).We take the direct obseration me thod of the focula distortion in crystal to measure the photorefractive threshol d value of these crystals and gained the result that the photorefractive thresho ld value of Zn(6mol%):LiNbO 3,Mg(5mol%):LiNbO 3 and Zn(3mol%):Mg(3mol%):LiNbO 3 increase above two orders of magnitude higher than pure LiNbO 3 crystal and the photorefractive threshold value of Zn(3mol%):LiNbO 3 and Mg(3mol%):LiNbO 3 is a little higher than that of pure LiNbO 3 crystal.The congruent compositio n ratio of LiNbO 3 is Li/Nb=0.946.A part of Nb 5+ take place Li + site to form the intrinsic defect antisite Nb 4+ Li .The charge transport proc ess in LiNbO 3 is due to this kind of intrinsic defect.Especially in high light intensity,the intrinsic defect is important.The quantity that make antisite Nb 4+ Li defect structure disappear when doping ions (Mg 2+ and Zn 2+ ) substitute for all Nb 4+ Li at Li + site is called the thre shold concentration for this impurity ion.At the same time the impurity ion star t to take place Nb site.The photo damage resistance impurity ion is to drive ant i site Nb Li from Li site to normal Nb site so that the OH - absorption peak shifts to 2.83μm from 2.87μm.The fact that the OH - absorption peak of Zn(3m ol%):Mg(3mol%):LiNbO 3 crystal shifts to 2.83μm from 2.87μm and its photo dam age resistance threshold value is two orders of magnitude higher than pure LiNbO 3 crystal shows that above analyse is reasonable.