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1.
玻璃的最大声子能量决定稀土离子的上转换发光强度,但本研究发现:Yb3+/Er 3+共掺锗碲酸盐玻璃在980nm LD抽运下,上转换荧光强度随着Bi2O 3对PbO的取代和碱 金属离子半径的增大而明显增强.而Raman光谱显示基质玻璃的最大声子能量并不随Bi 2O3对PbO的取代和碱金属离子半径的增大而变化,但玻璃的最大声子密 度随着Bi2O3对PbO 取代和碱金属离子半径的增大而降低.从玻璃无辐射跃迁概率的角度,通过分析表明,最大 声子密度的降低是玻璃上转换发光强度增强的主要原因. 相似文献
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研究了ErYb共掺的氟氧化物玻璃陶瓷的直接上转换敏化发光现象,发现其上转换机理主要是 Er3+与Yb3+离子间的能量传递上转换而不是Er3+离子 的步进多光子吸收.研究发现由于稀土离子优先富集到PbxCd1-xF2微晶中,形成数个稀土离子组成的耦合团,使其存在强烈的团簇效应,一方面导 致了上转换荧光非常强,另一方面也导致了上转换荧光随抽运激光功率的对数变化F-P曲线 存在逐
关键词:
直接上转换敏化
氟氧化物玻璃陶瓷
上转换合作辐射荧光 相似文献
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采用高温熔融法制备了组分为TeO2-ZnO-Na2O的Tm3+离子单掺和Tm3+/Yb3+共掺碲酸盐玻璃,应用Judd-Ofelt理论计算分析了玻璃样品的强度参量Ωt(t=2, 4, 6),自发辐射跃迁几率A,荧光分支比β和荧光辐射寿命τrad等光谱参量,测量得到了不同Yb3+离子掺杂浓度下玻璃样品的Tm3+离子上转换发光谱.结果显示,在980 nm泵浦光激励下玻璃样品发射出强烈的近红外上转换荧光.对Tm3+离子上转换发光分析表明,强烈的Tm3+离子近红外上转换发光主要来自于Yb3+/Yb3+离子间的共振能量传递以及基于单声子和双声子辅助的Yb3+/Tm3+离子间的非共振能量传递过程,并进一步计算得到了声子贡献比和能量传递系数.最后,计算分析了Tm3+:3F4→3H6能级间跃迁的1.8 μm波段吸收截面、受激发射截面和增益系数.研究表明,Yb3+/Tm3+共掺TeO2-ZnO-Na2O玻璃可以作为近红外波段固体激光器的潜在增益基质. 相似文献
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Z.X. Cheng S.J. ZhangF. Song H.C. GuoJ.R. Han H.C. Chen 《Journal of Physics and Chemistry of Solids》2002,63(11):2011-2017
Erbium and ytterbium codoped double tungstates NaY(WO4)2 crystals were prepared by using Czochralski (CZ) pulling method. The absorption spectra in the region 290-2000 nm have been recorded at room temperature. The Judd-Ofelt theory was applied to the measured values of absorption line strengths to evaluate the spontaneous emission probabilities and stimulated emission cross sections of Er3+ ions in NaY(WO4)2 crystals. Intensive green and red lights were measured when the sample were pumped by a 974 nm laser diode (LD), especially, the intensities of green upconversion luminescence are very strong. The mechanism of energy transfer from Yb3+ to Er3+ ions was analyzed. Energy transfer and nonradiative relaxation played an important role in the upconversion process. Photoexcited luminescence experiments are also fulfilled to help analyzing the transit processes of the energy levels. 相似文献
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研究了Er3+离子掺杂钡镓锗玻璃的吸收光谱、拉曼光谱和上转换光谱.分析了Er3+离子在钡镓锗玻璃中的上转换发光机理.结果表明:玻璃的最大声子能量为828cm-1,紫外截止波长为275nm.采用800nm和980nmLD激发玻璃样品,在室温下观察到强烈的上转换绿光和红光发射.随着Er3+离子浓度的增加,绿光发光强度先增加后减小,而红光发光强度呈单调递增趋势.能量分析表明:800nmLD激发产生的绿光主要源于Er3+离子4I13/2能级的激发态吸收过程;红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程.980nmLD激发产生的绿光主要源于Er3+离子4I11/2能级之间的能量转移过程;而红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程和4I13/2能级的激发态吸收过程.通过量子效率分析,发现采用800nmLD激发Er3+离子掺杂浓度为1mol% 的样品时,上转换绿光发光效率最高.
关键词:
上转换发光机理
3+离子掺杂')" href="#">Er3+离子掺杂
钡镓锗玻璃 相似文献
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Mo Ma Changfu Xu Liwen Yang Guozhong Ren Jianguo Lin Qibin Yang 《Physica B: Condensed Matter》2011,406(17):3256-3260
Stoichiometric Y7O6F9 powder codoped with Yb3+-Tm3+ was synthesized via co-precipitation and subsequent calcining route. The results of X-ray diffraction and transmission electron microscopy reveal that when the calcining temperature is beyond 800 °C, orthorhombic YF3 nanoparticles can be completely oxidized into orthorhombic Y7O6F9 powder. Under the excitation of a 980 nm laser, Y7O6F9 powder exhibits multicolor UC emission in regions spanning the UV to the NIR. In addition, the upconversion emission intensities of YF3, Y7O6F9 and Y2O3 powders were compared under the same dopant condition (Yb/Tm=5/0.5 mol%). The low phonon energy revealed by Raman spectra helped to understand the high efficient upconversion emission of Y7O6F9 and the main phonon vibration of Y7O6F9 lies at 472 cm−1, which is far lower that of Y2O3 (at 708 cm−1). Our results indicate that orthorhombic rare earth ions doped Y7O6F9 is an efficient matrix for UV and blue UC emission, and has potential applications in color displays, anti-counterfeiting and multicolor fluorescent labels. 相似文献
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Xinshun Wang Jianrong Qiu Juan Song Jian Xu Yang Liao Haiyi Sun Zhizhan Xu 《Optics Communications》2008,281(2):299-302
Near-infrared to ultraviolet upconversion luminescence was observed in the Pr3+:Y2SiO5 crystal with 120 fs, 800 nm infrared laser irradiation. The observed emissions at around 270 nm and 305 nm could be assigned to 5d → 4f transitions of Pr3+ ions. The relationship between the upconversion luminescence intensity and the pump power of the femtosecond laser reveals that the UV emission belongs to simultaneous three-photon absorption induced upconversion luminescence. 相似文献
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Impurity effect on the rare earth ion doped Sr0.6Ba0.4Nb2O6(SBN40) was studied at room temperature. Doping the rare earth ions of Pr3+ or Nd3+ changed the Raman profile: spectral broadening, central frequency shifts and relative intensity decreasing. Two reasons are considered according to the ferroelectric and optical properties of the rare earth ion doped SBN40: impurity-induced crystal disorder and the crystal structure change. SBN40 is the general disorder crystal and the disorder which is enhanced by doping the rare earth ion is especially strong along the x?y plane of the material compared with that along the polar C-axis. 相似文献
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A crystal field investigation of Er3+-doped Sc2O3 transparent ceramics is presented.The established energy level diagram is analyzed with crystal-field Hamiltonian of C2 symmetry including J-mixing effect. Very satisfactory correlations were obtained between 53 calculated and experimental Stark energy levels, with an rms of 7.7 cm−1. These results are compared with those reported for other rare earth ions in the same host and with Er3+ ions in other sesquioxides. The concordance between the crystal-field strength parameters indicates the consistence of our analysis. Furthermore, based on the extended electrostatic point charge model, a theoretical trend is proposed for rare earth ions in Sc2O3 in comparison with Y2O3. Based on this trend, very satisfactory results are obtained for Yb3+ ion in Sc2O3. 相似文献
12.
通过固相反应法制备了Er3+/Yb3+共掺杂ZrO2-Al2O3粉末的样品,并对样品在980nm激光激发下的上转换发光特性进行了研究.从发射光谱可以发现,在可见光范围内有3个强的发光带,一个位于654nm附近的红光带和两个分别位于545nm、525nm附近的绿光带,分别对应于Er3+离子的以下辐射跃迁:4F9/2→4I15/2、4S3/2→4I15/2、 2H11/2→4I15/2.其中又以Er3+离子的4F9/2→4I15/2跃迁产生的红色荧光辐射最强.对其上转换发光机制进行了分析,发现这三个发光过程都是双光子过程.对样品粉末进行了XRD检测,发现ZrO2主要以立方相为主,并且计算得到了这种立方结构的晶格常数.Al2O3固溶于ZrO2中,Al3+嵌入ZrO2后产生氧空位,导致ZrO2晶体的对称性降低,这种结构变化更有利于提高上转换效率,即上转换发光强度增强.
关键词:
3+/Yb3+')" href="#">Er3+/Yb3+
上转换
2-Al2O3')" href="#">ZrO2-Al2O3
荧光
稀土 相似文献
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The rare earth molybdenum sulfides RExMo6S8 (RE = rare earth) have been synthesized and are found to be superconducting with a few exceptions. This result, which is surprising in view of the high concentration of magnetic ions, is correlated with the particular structure of these compounds based on on units of Mo6S8. 相似文献
14.
T.K. Hatwar R.M. Nayak B.D. Padalia M.N. Ghatikar E.V. Sampathkumaran L.C. Gupta R. Vijayaraghavan 《Solid State Communications》1980,34(8):617-620
X-ray absorption spectroscopy technique is employed to determine the valence of the rare earth ions in EuCu2Si2, YbCu2Si2 and Sm4Bi3. In each case, two absorption peaks corresponding to two different valence states of respective rare earth ions have been observed. Low temperature (77 K) study of EuCu2Si2 indicates distinct change in the relative intensities of the absorption peaks compared to those registered at room temperature (300 K). It is inferred from the change in the relative intensities that the population of Eu2+ in EuCu2Si2 decreases at liquid nitrogen temperature compared to Eu3+. Conclusions drawn from these results agree well with those reported by others using different experimental techniques. In Sm4Bi3, Sm2+ and Sm3+ are found to occur in the ratio of 3:1. 相似文献
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Intense blue upconversion emission at 480 nm has been obtained at room temperature in Tm3+-Nd3+ co-doped Ta2O5 channel waveguides fabricated on a Si substrate, when the sample is excited with an infrared laser at 793 nm. The upconversion mechanism is based on the radiative relaxation of the Nd3+ ions (4F3/2 → 4I11/2) at about 1064 nm followed by the absorption of the emitted photons by Tm3+ ions in the 3H4 excited state. A coefficient of energy transfer rate as high as 3 × 10−16 cm3/s has been deduced using a rate equation analysis, which is the highest reported for Tm-Nd co-doped systems. The confinement of the 1064 nm emitted radiation in the waveguide structure is the main reason of the high energy transfer probability between Nd3+ and Tm3+ ions. 相似文献
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The efficiency of erbium three-micron laser (laser transition 4I11/2→4I13/2) depends essentially on the ratio of the parameters of active energy transfer upconversion (ETU) from the laser levels. The parameters of both ETU processes can be obtained from the analysis of the shape of the kinetics of the 4I11/2 level in concentrated Er:YAG crystals, under short pulse pumping. Mathematical modeling is used to evaluate the sensitivity of the method and to estimate the errors which can be introduced by the inhomogeneous pumping and accidental impurities. It was found that the ratio of the parameters corresponding to the ETU from the laser levels is less sensitive to the pumping inhomogeneities than that corresponding to the lower laser level. A reduction of this ratio with increasing erbium concentration is observed. 相似文献
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Ljubica R. Dja?anin Miroslav D. Drami?anin Svetlana R. Luki?-Petrovi? Dragoslav M. Petrovi? Marko G. Nikoli? 《Central European Journal of Physics》2012,10(2):519-523
Lithium-indium oxide is a high-density (5.9 g·cm−3), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient
phosphorescence when doped with Er3+ or Sm3+ ions. In this report, we demonstrate visible upconversion emission of Er3+-doped LiInO2 synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er3+ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared
excitation, and it is greatly enhanced by co-doping with Yb3+ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications
of this material as a low-temperature sensor. 相似文献
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采用共沉淀法制备了纳米晶ZrO2-Al2O3∶Er3+发光粉体.所制备的粉体室温下具有Er3+离子特征荧光发射,主发射在绿光,其中位于547 nm、560 nm的绿光最强,并得出稀土离子与基质之间有能量传递.对不同煅烧温度下的样品研究表明:因不同温度下所制得的样品晶相不同.研究了纳米晶ZrO2-Al2O3∶Er3+及ZrO2-Al2O3∶Er3+/Yb3+的上转换发光,并分析了上转换的跃迁机制.发现ZrO2-Al2O3∶Er3+的绿光为双光子过程,而ZrO2-Al2O3∶Er3+、Yb3+的上转换光谱中,红光和绿光也为双光子过程,而极弱的蓝光为三光子过程.讨论了Er3+的浓度猝灭现象.最适宜掺杂浓度的原子分数为2%(Er3+/Zr4+). 相似文献