Er3+/Nd3+/Tm3+共掺碲酸盐玻璃近红外发射和能量传递机理

为满足通信网络飞速发展对密集波分复用系统(DWDM)传输容量需求的不断增加,对DWDM系统核心器件掺铒光纤放大器(EDFA)性能的要求也越来越高。碲酸盐玻璃因其具有稀土离子溶解度高,声子能量低和高折射率等优点已成为替代传统掺铒石英光纤的理想材料。掺稀土碲酸盐玻璃可以作为宽带光纤放大器的理想增益介质来实现信号有效放大,因此提高掺铒碲酸盐玻璃光谱性能并拓展其放大带宽对DWDM系统扩容具有重要意义。通过Er³⁺、 Nd³⁺和Tm³⁺共同掺杂提高碲酸盐玻璃的放大带宽以获得超宽带发光。Er³⁺、 Nd³⁺和Tm³⁺分别通过跃迁产生1.55、 1.34和1.85μm波段的发光,且三个近红外发射波段基本相邻。采用三种离子共掺的方式,通过离子间发生能量传递(ET)来实现碲酸盐玻璃在连续光谱中的发光。在TeO₂-WO₃-ZnO-Na₂O-Er₂O₃碲酸盐玻璃中,先进...     

新型高掺Tm3+石英光纤制备及2.0μm激光性能研究

稀土掺杂石英光纤具有物化性能稳定、机械强度高、易于系统集成等优点，是目前光纤激光器最核心的增益介质，但其稀土掺杂浓度一般较低(<2%)。利用溶胶凝胶法和高温烧结工艺制备了Tm³⁺掺杂浓度为8.29×10²⁰ cm^-3的高硅氧玻璃，并表征了其光谱性能。采用溶胶镀膜和二次熔融拉锥方法制备了芯径约为4μm、外径为125μm的石英光纤，其可与商用无源光纤进行熔接。利用全光纤化线性腔结构，以制备的不同长度掺Tm³⁺石英光纤作为增益介质，均可实现1947 nm激光输出，光信噪比约为70 dB；当光纤长度为4.6 cm时，斜率效率高达14.1%；同时搭建了掺铥光纤放大器，测得光纤小信号净增益系数为0.48 dB/cm。研究结果表明，该新型光纤制备方法可为高浓度掺铥石英光纤提供新途径，有望推动其在2.0μm单频及高重频锁模光纤激光器中的应用。     

Tm3+/Ho3+共掺碲酸盐微结构光纤激光器

用棒管法拉制了Tm³⁺/Ho³⁺掺杂的碲酸盐微结构光纤,并获得了2 μm的激光输出。以1 560 nm的Er³⁺掺杂石英光纤激光器作为泵浦源,在22 cm长的微结构光纤中,得到了最大功率为8.34 mW、波长为2 065 nm的连续激光输出,泵浦光功率为507 mW,斜率效率为2.97%。研究结果表明,Tm³⁺/Ho³⁺共掺碲酸盐微结构光纤是一种用于研制2 μm激光器的理想材料。     

Er3+/Yb3+共掺碲硼硅酸盐玻璃的光谱性质和热稳定性研究

制备了系列Er³⁺/Yb³⁺共掺碲硼硅酸盐玻璃样品(85-x)TeO₂-15B₂O₃-xSiO₂ (TBS x=0,5,10,15,20 mol%).测试和分析了样品的吸收光谱、荧光光谱、能级寿命、红外透射光谱及差热特性.并通过对Er³⁺离子⁴I_13/2→⁴I_15/2跃迁发射谱线的高斯拟合，设计了一个简单的四能级结构估算了Er³⁺离子⁴I_13/2和⁴I_15/2能级在碲硼硅酸盐中的Stark分裂情况.研究表明SiO₂的引入能有效地改善玻璃的热稳定性和光谱性能，玻璃析晶温度T_x与玻璃转变温度T_g之差(ΔT=T_x-T_g)可达178℃，说明碲硼硅酸盐是一种适合于光纤拉制的玻璃基质材料.比较了不同基质玻璃中Er³⁺离子的荧光半高宽和受激发射截面，结果表明TBS玻璃系统具有较好的带宽性能，是一种优良的宽带光纤放大器候选基质材料. 关键词： 碲硼硅酸盐 热稳定性 高斯拟合 -基')" href="#">OH^-基     

掺Yb3+双包层光纤激光器的数值分析

 对掺Yb³⁺双包层光纤激光器不同参数情况下的输出功率和增益分布进行了数值模拟，分析了一端泵浦和双端泵浦方式下输出特性的差异，激光沿光纤长度方向的分布，输出功率与光纤长度、腔镜反射率及泵浦功率的关系。结果显示：两端泵浦较一端泵浦增益更加平坦，输出功率也稍高；当泵浦光波长为975nm时，输出激光功率对光纤长度更为敏感，最佳光纤长度相对于泵浦光波长为915nm时短且转化效率高；在大功率长光纤的情况下，光纤有损耗时输出功率随输出腔镜反射率的增加单调地减小，无损耗时输出功率不随输出腔镜反射率变化。     

Er3+/Ce3+共掺TeO2-Bi2O3-TiO2玻璃的热稳定性和光谱特性研究

用高温熔融法制备了Er³⁺/Ce³⁺共掺新型碲酸盐玻璃(TeO₂-Bi₂O₃-TiO₂).采用差热分析方法研究了玻璃的热稳定性,测试并分析了不同Ce³⁺离子掺杂浓度下Er³⁺离子的吸收光谱、上转换光谱和荧光光谱特性.研究结果表明,制备的碲酸盐玻璃具有很好的热稳定性,玻璃析晶温度Tx与玻璃转变温度Tg之差(ΔT=Tx-Tg)达到了185 ℃,高于其它文献的报道|同时,Ce3+离子共掺引入的能量转移(Ce³⁺∶2F5/2+Er³⁺∶4I11/2→Ce³⁺∶2F7/2+Er³⁺∶4I13/2)有效地抑制了Er³⁺离子上转换发光并显著增强了1.53 μm波段荧光强度,而发射截面随着Ce³⁺离子掺杂浓度相应增大.优异的热稳定性以及光谱性能揭示Er³⁺/Ce³⁺共掺碲酸盐玻璃是一种潜在的制备宽带掺铒光纤放大器的理想增益介质.     

掺Yb3+双包层大模场面积光纤锁模激光器

报道了一种结构简单、运转稳定并可以输出高脉冲能量的被动锁模光纤激光器.激光器的增益介质为掺Yb³⁺双包层大模场面积光纤,具有非常低的非线性系数.利用非线性偏振旋转效应和半导体可饱和吸收镜结合实现自启动锁模,获得了平均功率为160mW、重复频率为55.9MHz(对应于3nJ的单脉冲能量)、脉冲宽度为10.6ps的激光脉冲输出. 关键词： 大模场面积光纤 光纤激光器 锁模     

掺Er3+氟化物光纤振荡器中红外超短脉冲的产生

基于非线性薛定谔方程建立了氟化物(ZrF₄-BaF₂-LaF₃-AlF₃-NaF, ZBLAN)光纤振荡器中产生中红外超短脉冲的理论模型, 在此基础上研究了中红外超短脉冲在氟化物光纤振荡器中形成的物理机理, 数值模拟了氟化物光纤振荡器中中红外超短脉冲的演化过程. 分析了腔内净色散和小信号增益系数对振荡器中锁模脉冲产生的影响, 并给出了参数设置范围. 研究发现: 当掺Er³⁺氟化物光纤长度, 小信号增益系数, 不饱和损耗为一定值时, 腔内净色散在一定范围内才会出现稳定的锁模脉冲, 且随着腔内净色散增加脉冲宽度变宽, 光谱变窄, 峰值功率降低; 当掺Er³⁺氟化物光纤长度及不饱和损耗一定, 腔内净色散量为合理值, 小信号增益系数在合理的范围时可以得到稳定的锁模脉冲, 且随着小信号增益系数的增加脉冲宽度变宽, 光谱变宽, 峰值功率增加.     

共沉淀法制备Y2O2S：Eu3+,Mg2+,Ti4+红色长余辉材料

用共沉淀法制备了Y₂O₂S:Eu³⁺,Mg²⁺,Ti⁴⁺红色长余辉材料。测量了材料的电子显微形貌、晶体结构和发射光谱。通过与固相法制备的Y₂O₂S:Eu³⁺,Mg²⁺,Ti⁴⁺长余辉材料比较,发现两种方法都可以制备粒度基本相同的纯相Y₂O₂S基质晶体,但共沉淀法样品的颗粒结构更松散。研究了Eu³⁺浓度对两种方法制备样品的谱线发射强度的影响,通过比较共沉淀法和高温固相法制备的样品中Eu³⁺的⁵D₁→⁷F₃较高能级跃迁的587.6nm谱线强度随Eu³⁺浓度的变化,发现共沉淀法更有利于Eu³⁺均匀进入Y₂O₂S基质晶格而形成有效的发光中心。     

高光强激发下Er3+/Yb3+共掺TiBa玻璃的绿光上转换发光

制备了Er3+Yb3+共掺微米级高折射率TiBa玻璃颗粒和微球,玻璃基材主要成分为TiO2BaCO3Ba(NO3)2CaCO3SiO2等,掺入1mol%Er2O3+3mol%Yb2O3.用976nm激光激发测量了它们的上转换绿光发射,发现当抽运功率大于30mW(功率密度约为1000W·cm-2)时,524nm峰的强度大于547nm峰的强度,随功率的增大,其强度差越来越大,实验判断,这是由于材料吸收抽运光而升温所致 关键词： 上转换发光 掺Er3+Yb3+玻璃 微球     

Fine structure and isotope shift of the 3s4d 3 D-3s3p 3 P, 3s5d 3 D-3s3p 3 P and 3p 2 3 P-3s3p 3 P Transitions of MgI

Summary We report the measurements of the³ D(3s4d)-³ P(3s3p)³ D(3s5d)-³ P(3s3p), and³ P(3p ²)-³ P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between²⁴Mg and²⁶Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of theI ₂ transitions used as a reference and by the precision in the knowledge of the related wavelengths.     

LaGaO3:RE3+(RE3+=Eu3+,Ho3+)的光谱

本文用固态反应合成了钙钛矿型的LaGaO3和LaGaO3:RE3+(RE3+=Eu3+,Ho3+)荧光体,并观察了物相随不同的激活离子浓度的变化。测量了化合物在室温下的反射光谱,激发光谱和荧光光谱。研究了Eu3+的D0→7F2和Ho3+的5S2→5I8的荧光强度与激活离子浓度的关系,发现了浓度猝灭,并得到了最大荧光强度的浓度值。     

The gas phase infrared band contours of s-triazine and s-triazine-d3: The fundamentals of C3N3H3 and C3N3D3 and some overtone and combination bands of C3N3H3

The systematic application of band contour techniques to account for most of the observed features of the ir spectra of s-triazine and s-triazine-d₃ have been made as well as a critique as to the limitations of such methods. The experimental and computer methods used to study the gas phase infrared band contours of s-triazine and s-triazine-d₃ are out-lined. Contours of the five E′ fundamentals of s-triazine have been recorded under moderate resolution and analyzed to give the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$, i = 6–10. The effects of l-resonance are very apparent for ν₈ and ν₉, in the form of holes in the Q branches of these bands. Under the highest resolution available, ν₆ and ν₁₀ also show l-resonance effects. Values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ were obtained for these four fundamentals. One of the parallel A₂″ fundamentals of C₃H₃N₃ (ν₁₂) has also been studied. It lies close to ν₁₀(E′) and an A × E type of second-order Coriolis resonance may be the cause of the intensity enhancement observed in the inner wings of the ν₁₂ and ν₁₀ bands. Hot bands of the type (ν_i + nν₁₄ ? nν₁₄) have been observed in the contours of ν₈, ν₁₀, and ν₁₂. This is felt to be responsible for the large difference between our observed zeta sum (?1.30) and the theoretical sum (?1.00).The gas phase infrared band contours of the five E′ and 2A₂″ fundamentals of C₃N₃D₃ have also been recorded under moderate resolution. From P-R separations and by computer simulation of the contours, values of the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$ have been obtained for the E′ modes. The effects of l-resonance have been observed for ν₈(E′) and ν₁₀(E′) and values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ have been estimated. An extensive series of hot bands of the type (ν₁₂ + nν₁₄ ? nν₁₄) has been observed in the contour of the ν₁₂ (A₂″) fundamental. The mass effect on the Coriolis constants has been discussed.Infrared band contours of the overtone 2ν₇ and seven degenerate E′ combination bands of C₃N₃H₃ have been recorded under moderate resolution. Analysis of these contours using the P-R separation method and computer simulation of the contours has given values of $\text{ζ}{}_{\mathrm{<mtext>eff</mtext>}}{}^{\mathrm{z}}$ for these bands. Fermi resonance between 2ν₇ and ν₆ has been analyzed. The importance of considering both the observed contour as well as the observed frequency when assigning higher tone bands is illustrated.     

Infrared spectra of matrix isolated BH3NH3, BD3ND3, and BH3ND3

The infrared spectra of ammonia-borane, BH₃NH₃, and two of its deuterated isotropic species, BD₃ND₃ and BH₃ND₃, isolated in argon matrix at liquid hydrogen temperature have been measured. Well resolved bands for these three isotopic species have been observed for all the fundamentals. A complete frequency assignment based on C₃v molecular symmetry has been made. A set of force constants have been calculated from the data for the two isotopes BH₃NH₃ and BD₃ND₃ using a valence force field. The agreement between experiment and frequencies calculated from these force constants for the mixed isotopic species, BH₃ND₃, substantiates the present assignment.     

Dielectric investigations of solid solutions SrTiO3-KTaO3 and SrTiO3-KNbO3

The temperature dependences of the dielectric constant and dielectric hysteresis loops in ceramic samples of (1 ? x)SrTiO_3?x KNbO₃ and (1 ? x)SrTiO_3?x KTaO₃ (0 ≤ x ≤ 0.3) solid solutions prepared using different heat treatments have been investigated. Phase diagrams of the studied solid solutions have been constructed in the T-x coordinates. It has been shown that, after quenching of samples (spontaneous cooling at room temperature after long-term heating at the sintering temperature of the ceramic samples), the temperature of the induced phase transition increases because of the weakening of random electric fields associated with nonisovalent impurities due to their “frozen” nonequilibrium redistribution. For small concentrations x, strong dielectric relaxation is observed in the temperature range of 150–250 K. A model of relaxing centers, which is based on the local charge compensation of heterovalent impurities, has been proposed.     

O_3 fast and simple treatment-enhanced p-doped in Spiro-MeOTAD for CH_3NH_3I vapor-assisted processed CH_3NH_3PbI_3 perovskite solar cells

We demonstrate a simple and fast post-deposition treatment with high process compatibility on the hole transport material(HTM) Spiro-MeOTAD in vapor-assisted solution processed methylammonium lead triiodide(CH_3NH_3PbI_3)-based solar cells. The prepared Co-doped p-type Spiro-MeOTAD films are treated by O_3 at room temperature for 5 min,10 min, and 20 min, respectively, prior to the deposition of the metal electrodes. Compared with the traditional oxidation of Spiro-MeOTAD films overnight in dry air, our fast O_3 treatment of HTM at room temperature only needs just 10 min,and a relative 40.3% increment in the power conversion efficiency is observed with respect to the result of without-treated perovskite solar cells. This improvement of efficiency is mainly attributed to the obvious increase of the fill factor and short-circuit current density, despite a slight decrease in the open-circuit voltage. Ultraviolet photoelectron spectroscopy(UPS) and Hall effect measurement method are employed in our study to determine the changes of properties after O_3 treatment in HTM. It is found that after the HTM is exposed to O_3, its p-type doping level is enhanced. The enhancement of conductivity and Hall mobility of the film, resulting from the improvement in p-doping level of HTM, leads to better performances of perovskite solar cells. Best power conversion efficiencies(PCEs) of 13.05% and 16.39% are achieved with most properly optimized HTM via CH_3NH_3I vapor-assisted method and traditional single-step method respectively.     

Far Infrared Spectra of Ammonia-Boron Trifluoride: NH3BF3 and ND3BF3

Abstract

Spectra of polycrystalline samples of NH₃BF₃ and ND₃BF₃ at 300 K and 98 K have been recorded in the frequency range 20-400 cm^?1. Isotopic frequency ratios are used to interpret the observed features in terms of the known molecular and crystal structures.     

Ba3La(BO3)3基质中Tb3+的光致发光

以高温固相法合成了Ba3La(BO3)3∶Tb3 发光材料。在254nm紫外光激发下,研究了Ba3La(BO3)3∶Tb3 的激发光谱、发射光谱、发光强度与Tb3 浓度的关系。确定了Ba3La(BO3)3基质中Tb3 的自身浓度猝灭机理;探讨了助熔剂LiCO、敏化剂Ce3 、Bi3 的加入对荧光粉的发光强度的影响。     

Terahertz Vibrational Modes in CH3NH3PbI3 and CsPbI3 Perovskite Films

JETP Letters - Films of CH3NH3PbI3 organometallic perovskite, which is currently considered as a promising basic material for new-generation solar cells, as well as films containing CsPbI3...