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1.
《Optical Materials》2008,30(12):1662-1666
Yb:Y3Al5O12 (Yb:YAG) single crystals with Yb doping concentration 0.5 at.%, 5 at.%, 15 at.%, 25 at.%, 50 at.%, 100 at.% and Yb:YAlO3 (Yb:YAP) single crystals with Yb doping concentration 0.5 at.%, 5 at.%, 15 at.%, 30 at.% were grown by the Czochralski process. The fluorescence spectra of these crystals and the effects of self-absorption on the shape of the fluorescence spectra were studied. Through comparing the fluorescence spectra of Yb:YAG and Yb:YAP, all results indicate that the effects of self-absorption on the fluorescence spectra of Yb:YAP are remarkably stronger than that of Yb:YAG at the same Yb concentration. 相似文献
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Single crystal of Yb:GdYAl3(BO3)4(Yb:GdYAB) has been grown by the flux method. The structure of Yb:GdYAB crystal has been determined by X-ray diffraction analysis. The experiment show that the crystal has the same structure as that of YAl3(BO3)4 crystal and its unit cell constants have been measured to be a = 9.30146 Å, c = 7.24164 Å, Vol = 542.59 Å3. The absorption and fluorescence spectrum of Yb:GdYAl3(BO3)4 crystal have also been measured at room temperature. In the absorption spectra, there are two absorption bands at 938 nm and 974 nm, respectively, which is suitable for InGaAs diode laser pumping. In the fluorescence spectra, there are two fluorescence peaks at 992 and 1040 nm. The thermal properties of Yb:GdYAl3(BO3)4 crystal have been studied for the first time. The thermal expansion coefficient along c-axis is almost 5.4 times larger than that along a-axis. The specific heat of the crystal has been measured to be 0.77 J/g °C at room temperature. The calculated thermal conductivity is 5.26 Wm−1 K−1 along a-direction. 相似文献
4.
Fei Tang Jiquan HuangWang Guo Wenchao WangBinjie Fei Yongge Cao 《Optical Materials》2012,34(5):757-760
Yb:YAG transparent ceramics with different doping concentration were fabricated by the traditional solid-state diffusion route, and their fluorescence properties and laser behavior were investigated. It is found that both the fluorescence intensity and lifetime depend deeply on both the doping concentration of Yb ions and the annealing treatment. The continuous wavelength (C.W.) laser performance for 10 at.% Yb:YAG ceramic suggests that both the threshold pump power and slope efficiency increase with increasing transmittance of the output couple (Toc). For Toc = 15%, the threshold pump power is about 6.1 W, the slope efficiency is 25%, and the maximum output power of 2.2 W is achieved when pumped by 14.9 W. 相似文献
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Yongjun Dong Guoqing Zhou Jun Xu Guangjun Zhao Fenglian Su Liangbi Su Hongjun Li JiLiang Si Xiaobo Qian Xiaoqing Li Jun Shen 《Optical Materials》2006,28(12):1377-1380
Gamma-ray irradiation induced color centers and charge state recharge of impurity and doped ion in 10 at.% Yb:YAP have been studied. The change in the additional absorption (AA) spectra is mainly related to the charge exchange of the impurity Fe2+, Fe3+ and Yb3+ ions. Two impurity color center bands at 255 and 313 nm were attributed to Fe3+ and Fe2+ ions, respectively. The broad AA band centered at 385 nm may be associated with the cation vacancies and F-type center. The transition Yb3+ → Yb2+ takes place in the process of γ-irradiation. Oxygen annealing and γ-ray irradiation lead to an opposite effect on the absorption properties of the Yb:YAP crystal. In the air annealing process, the transition Fe2+ → Fe3+ and Yb2+ → Yb3+ take place and the color centers responsible for the 385 nm band was destroyed. 相似文献
6.
Qi Song Cheng-Ren Li Jian-Yong Li Wan-Yu Ding Shu-Feng Li Jun Xu Xin-Lu Deng Chang-Lie Song 《Optical Materials》2006,28(12):1344-1349
The Yb:Er co-doped Al2O3 thin film was deposited on oxidized silicon wafers by microwave ECR plasma source enhanced RF magnetron sputtering, and annealed from 800 °C to 1000 °C. The photoluminescence at 1.53 μm of thin film was obtained under room temperature. The mixture phase structure of γ and θ is observed by XRD, and the compositions of the thin film are investigated by EPMA. The maximum PL intensity was achieved with O2:Ar at 1:1, annealing temperature at 900 °C, and experimental ratio of Yb:Er at 1:3.6. The energy transfer mechanism between Er and Yb ions is supported by theoretical analysis and experiment results. 相似文献
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采用温度梯度法生长了0.5at% Nd、xat% Sc:CaF2(x=0, 2, 5, 8)系列晶体, 测试了晶体的吸收光谱、荧光光谱和荧光寿命。研究发现发射强度和荧光寿命随着Sc3+离子浓度的增加而提高。通过改变Sc3+离子的浓度发现, 当掺杂5at% Sc3+时可以获得最大的吸收截面为1.42×10-20 cm2。另外, 掺入Sc3+使共掺晶体在吸收光谱796 nm处产生新峰。综上, 通过调节Sc3+离子浓度, 可以改变Nd3+离子的局域结构, 优化晶体的光谱性能。 相似文献
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Y. Kalisky C. Labbe K. Waichman L. Kravchik U. Rachum P. Deng J. Xu J. Dong W. Chen 《Optical Materials》2002,19(4):403-413
We investigate the repetitive modulation in the kHz frequency domain of a passively Q-switched, diode-pumped Yb:YAG laser, by Cr4+:YAG, Cr4+:LuAG, and Cr4+:GSGG saturable absorbers. The results presented here are focused towards the design of a passively Q-switched Yb:YAG microlaser. The free-running performance of both rod and a disk Yb:YAG is characterized and experimental parameters such as gain and loss are evaluated. These values, together with the value of the stimulated emission cross-section, e.g. σem=3.3×10−20 cm2 were found to fit between our experimental results and an existing numerical model which relates the experimental and physical parameters to the minimal threshold pumping power. Q-switched pulses with maximum peak power of ≈10.4 kW, with energy of ≈0.5 mJ/pulse, were extracted with 30% extraction efficiency. 相似文献
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The effect of radiation trapping on the emission properties of Er3+-doped tellurite and phosphate glasses has been investigated as the function of sample thickness and doping concentration. It was found that radiation trapping exists generally in two glass matrices, even at low doping concentration (0.1 mol% Er2O3). The larger effect of radiation trapping in tellurite glasses compared with phosphate glasses is due to its larger emission cross-section at 1.5 μm band and the spectral overlap between the emission and absorption spectra of Er3+: 4I13/2 ↔ 4I15/2transition. Due to radiation trapping, the measured lifetime of the Er3+: 4I13/2 level in tellurite glasses increases by about 11–37% with increasing the sample thickness at the different erbium doping concentration, while 6–17% for phosphate glasses. And the full-width at half maximum of fluorescence (FWHM) of Er3+: 4I13/2 → 4I15/2 transition in tellurite glasses increased by about 15–64% with increasing the sample thickness, while 11–55% for phosphate glasses. It caused a high overestimation on the figure of merits (FOM) for amplifier bandwidth (σe × FWHM). 相似文献
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掺Yb3+闪烁晶体是新近发展起来的一类闪烁体,有可能用于探测太阳中微子.本文简要介绍了掺Yb3+闪烁晶体的电荷迁移发光的机理以及基质晶体对温度猝灭与浓度猝灭的影响.综述了具有石榴石结构和钙钛矿结构的两类掺Yb3+闪烁晶体的研究进展,特别是Yb:YAG和Yb:YAP晶体的生长、闪烁性能以及应用前景.最后,对掺Yb3+闪烁晶体的未来研究方向做了展望. 相似文献
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采用热键合技术制备了Yb:Y3Al5O12/Y3Al5O12(Yb:YAG/YAG)复合晶体,对复合晶体进行了结构表征和键合质量检测.利用光学显微镜和扫描电镜观察了复合晶体横截面的形貌;在偏光显微镜下观察键合区域的应力,利用干涉条纹来表征复合晶体的光学均匀性;通过红外透过光谱的测量来检测复合晶体的键合质量.实验结果表明:热键合技术制备的Yb:YAG/YAG复合晶体键合界面处无界面缺陷,不存在复合界面空间过渡层,光学均匀性良好. 相似文献
12.
Jun Dong Guozhang XuJian Ma Mengjun CaoYing Cheng Ken-ichi UedaHideki Yagi Alexander A. Kaminskii 《Optical Materials》2012,34(6):959-964
Continuous-wave and passively Q-switched microchip laser performance of Yb:YAG ceramics and single-crystals was investigated. Highly efficient continuous-wave Yb:YAG laser performance was observed at 1030 nm and 1049 nm for both Yb:YAG ceramics and crystals with different transmissions of output couplers. The laser performance of Yb:YAG ceramic is comparable to that of Yb:YAG single crystal. Meanwhile, the laser performance of laser-diode pumped Yb:YAG/Cr4+:YAG all-ceramics- and all-crystals-combination passively Q-switched microchip lasers were investigated. Sub-nanosecond laser pulses with peak power over 150 kW were obtained with different Yb:YAG/Cr4+:YAG combinations. Linearly polarized laser was observed in Yb:YAG/Cr4+:YAG all-crystals combination and circular polarized laser was obtained in Yb:YAG/Cr4+:YAG all-ceramics combination. The best laser performance was obtained with Yb:YAG/Cr4+:YAG all-crystals combination. 相似文献
13.
Dhiraj K. Sardar Santiago Vizcarra Mohammad A. Islam Toomas H. Allik Edward J. Sharp Albert A. Pinto 《Optical Materials》1994,3(4):257-263
Spectroscopic and EPR investigations of Nd3+-doped CaZn2Y2Ge3O12 (CAZGAR) have been performed. The absorption, fluorescence, excitation spectra and fluorescence lifetime have been measured at room temperature. The Judd-Ofelt theory has been applied to the measured optical absorption intensities to predict the radiative decay rates, branching ratios, and peak stimulated emission cross section from the metastable 4F3/2 state to the 4I9/2 manifold. The fluorescence lifetime of the 4F3/2 level of Nd3+ at low concentration in this host was measured to be 285 ± 10 μs, which is longer than that for Nd3+: YAG. Color centers located at zinc octahedral sites have been produced in these crystals by ultraviolet irradiation and have been detected by EPR techniques. The effects of the color centers on the potential laser characteristics of this materials are discussed. 相似文献
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Xiaojiang Pei Yanbing Hou Suling Zhao Zheng Xu Feng Teng 《Materials Chemistry and Physics》2005,90(2-3):270-274
In this paper, YLiF4 codoped with Tm3+ and Yb3+ ions was synthesized by hydrothermal method. Yb3+ concentration is fixed at 1.5%, and Tm3+ concentration is changed from 0.1 to 0.4%. Intense upconversion luminescence is observed when the samples are excited by 980 nm. The dependence of upconversion luminescence on Tm3+ concentrations is presented. The results show that upconversion luminescence increases with the Tm+ concentration and gets its peak at 0.3 mol%. Under the excitation of 980 nm, the blue emission of 479 nm and the red emission of 647 nm are both duo to two photons process, and the UV emission of 361 nm is attributed to the three photons process. We also analyse the upconversion mechanism and process. 相似文献
15.
Jianjun Xie Jingying Liao Zhengsong Geng Chongzhi Ye Hui Yuan Wei Xiong Dunhua Cao Zhonggui Zhan Liang Chen Bingfu Shen Zhiwen Yin 《Materials Science and Engineering: B》2006,130(1-3):31-35
The effects of Y3+ doping at different concentration on the luminescnece properties of PbWO4 crystals have been investigated by means of Fourier transform infrared (FT-IR) spectrum, optical transmission, thermoluminescence (TL), X-ray excited luminescence (XEL), photoluminescence (PL) under excitation of UV light and light yield measurements. The series PbWO4:Y crystal samples were grown by modified Bridgman method and the concentration of Y3+ in the melt was in the range of 0–1.0 mol%. The slight blue-shift and evident red-shift of the absorption edge in PbWO4 crystal were observed at low and heavy doping concentration, respectively. TL peaks in the range of from room temperature to 250 °C disappeared after the doping with Y3+. With the increase of doping concentration, the luminescence intensity in the XEL and PL spectra was found to decrease accordingly, especially in the case of heavy doping. The measuring results demonstrate that Y3+ doping concentration below 100 ppm in the crystal seems to be the best for optimizing the optical and scintillation properties of the material. The mechanism of Y3+ doping concentration influence on luminescence was also discussed in this paper. 相似文献
16.
Fugui Yang Chaoyang Tu Hongyan Wang Yanping Wei Zhenyu You Guohua Jia Jianfu Li Zhaojie Zhu Xiuai Lu Yan Wang 《Optical Materials》2007,29(12):1861-1865
Single-crystal ZnWO4:Dy3+ was grown by Czochralski technique. The XRD, absorption spectra as well as fluorescence spectrum are investigated and the Judd–Ofelt intensity parameters Ω2, Ω4, Ω6 are obtained to be 7.76 × 10−20 cm2, 0.57 × 10−20 cm2, 0.31 × 10−20 cm2, respectively. Calculated radiative transition rate, branching ratios and radiative lifetime for different transition levels of ZnWO4:Dy3+ crystals are presented. Fluorescence lifetime of 4F9/2 level is 158 μs and quantum efficiency is 66%.The most intense fluorescence line at 575 nm correlative with transition 4F9/2 → 6H13/2 is potentially for application of yellow lasers. 相似文献
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O. Guillot-Noël B. Viana B. Bellamy D. Gourier G. B. Zogo-Mboulou S. Jandl 《Optical Materials》2000,13(4):427-437
Nd3+ : YVO4 is one of the most interesting laser hosts for micro and diode-pumped solid state lasers. We have studied magnetic and optical properties of Nd3+ in three zircon type crystals YMO4 (M=V, As, P). In particular, Nd3+ ions exhibit in the three hosts a multisite character observed in the absorption and emission spectra. However, the emission and its dynamics are strongly dependant on the reabsorption mechanisms. In Nd : YVO4, single crystals containing 7 ± 1 × 1018 Nd3+ ions/cm3, the lifetime is 95 ± 2 μs in good agreement with the calculated radiative lifetime. Electron Paramagnetic Resonance (EPR) measurements are performed to identify the nature of the different substitution sites for Nd3+ ions. Nd3+ ions are found to be inhomogeneously distributed in tetragonal D2d symmetry sites, in isolated ions, “shallow clusters” and pairs. Proportions of the different local environments depend on the total neodymium concentration. For instance, 15% of the Nd3+ ions are gathered in Nd3+–Nd3+ pairs for 7.2 ± 0.2 × 1019 Nd3+ ions/cm3. 相似文献
18.
M. Malinowski R. Piramidowicz Z. Frukacz G. Chadeyron R. Mahiou M. F. Joubert 《Optical Materials》1999,12(4):409-423
Emission from the high lying excited states, energy transfer, and upconversion processes are investigated in YAlO3:Ho3+. Selectively excited emission spectra in the range from 300 to 800 nm starting from the 3D3, 3G5, 5F3, 5S2 and 5F5 multiplets were measured at 15 K. This, together with the detailed absorption and excitation measurements at 15 K allowed determination of the Stark energy levels of Ho3+ ions in YAlO3 up to UV energies. The 5S2 fluorescence decays were recorded as a function of temperature and Ho3+ concentration in order to investigate the process of quenching of fluorescence due to cross relaxation among two ions. Conversion of red and infrared laser radiation to green 5S2 and blue 5F3 emission is reported. Under pulsed resonant excitation of the 5F5 or 5I5 levels the upconversion was found to be due to energy transfer process between two excited ions. The photon avalanche effect was observed under cw excitation around 585 nm. 相似文献
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The synthesis and photoluminescent (PL) properties of calcium stannate crystals doped with europium grown by mechanically activated in a high energy vibro-mill have been investigated. The characteristics of Ca2SnO4:Eu3+ phosphors were found to depend on the amounts of europium ions. The XRD profiles revealed that the system, (Ca1−xEux)2SnO4, could form stable solid solutions in the composition range of x = 0–7% after being calcined at 1200 °C. The calcined powders emit bright red luminescence centered at 618 nm due to 5D0 → 7F2 electric dipole transition. Both XRD data and the emission ratio of (5D0 → 7F2)/(5D0 → 7F1) reveal that the site symmetry of Eu3+ ions decreases with increasing doping concentration. The maximum PL intensity has been obtained for 7 mol% concentration of Eu3+ in Ca2SnO4. 相似文献