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1.
We have examined the fluorescence characteristics of the garnet-type crystal Yb 3Al 5O 12 : Er 3+ (YbAlG : Er 3+) and studied the energy transfer process between the two rare earth ions over a temperature range 78–297 K. Certain data were compared with those of YAlG : Er 3+. In YbAlG : Er 3+, Yb fluorescence is observed at ?1.03 μm (corresponding to the 2F 5/2 → 2F 7/2 transition); Er fluorescence occurs at ?8500 Å ( 4S 3/2 → 4I 13/2 transition) and ?1.6 μm ( 4I 13/2 → 4I 15/2 transition). In YAlG : Er 3+, the same Er lines are observed with the addition of a band at ?1 μ ( 4I 11/2→ 4I 15/2 transition). In YbAlG : Er 3+, the decay pattern of the Yb emission is purely exponential at all the temperatures examined; the fluorescence lifetime ranges from 36 μ s (at 78 K) to 74 μs(at 269 K). The lifetime of the Er 4I 13/2 level in the same sample increases from 5.4 ms (at 78 K) to 6.85 ms (at 294 K). The lifetime of this Er level in YAlG : Er 3+ is weakly temperature dependent over the same range with a value of ?12 ms. Excitation spectra were obtained for the Er 1.53 μm fluorescence in YbAlG : Er 3+ in order to verify the presence of Yb → Er energy transfer in this sample. The presence of the Yb absorption band (?1 μm) in these spectra provides direct evidence of this energy transfer. The relative enhancement of this Yb band with respect to the Er bands in going from 78 K to 175 K is an indication of a more efficient transfer at the higher temperature. Excitation spectra obtained for the Yb 1.03 μm fluorescence in YbAlG : Er 3+ revealed the presence of Er → Yb energy transfer as well in this sample. The existence of both Yb → Er and Er → Yb transfer is expected, due to the resonance between the 4I 11/2 → 4I 15/2 transition of Er and the 2F 5/2 → 2F 7/2 transition of Yb. The above results are explained in terms of a rate equation model in which transfer in both directions is treated in the following manner: Yb → Er transfer is considered to be much more probable than decay processes originating at the Yb 2F 5/2 level; Er → Yb transfer is treated as much more probable than decay processes originating at the Er 4I 11/2 level. 相似文献
2.
An Er:Yb:Sr 3Gd 2(BO 3) 4 crystal was grown by the Czochralski method. The polarized spectral properties of the crystal were investigated, including
the polarized absorption and fluorescence spectra and fluorescence decay. The fluorescence quantum efficiency of the upper
laser level 4I 13/2 of Er 3+ ions and the efficiency of the energy transfer from Yb 3+ to Er 3+ ions were calculated. End-pumped by a diode laser at 970 nm in a hemispherical cavity, a 1.6 W quasi-cw laser at 1.5–1.6 μm
with a slope efficiency of 18% and an absorbed pump threshold of 5.9 W was achieved in a 1.8-mm-thick Z-cut Er:Yb:Sr 3Gd 2(BO 3) 4 crystal. This crystal has a flat and broad gain curve at 1.5–1.6 μm and so is also a potential gain medium for tunable and
short pulse lasers. 相似文献
3.
Wide band gap Yb 3+ and Er 3+ codoped ZrO 2 nanocrystals have been synthesized by a modified sol-gel method. Under 967 nm excitation strong green and red upconversion emission is observed for several Er 3+ to Yb 3+ ions concentration ratios. A simple microscopic rate equation model is used to study the effects of non-radiative direct Yb 3+ to Er 3+ energy transfer processes on the visible and near infrared fluorescence decay trends of both Er 3+ and Yb 3+ ions. The microscopic rate equation model takes into account the crystalline phase as well as the size of nanocrystals. Nanocrystals phase and size were estimated from XRD patterns. The rate equation model succeeds to fit simultaneously all visible and near infrared fluorescence decay profiles. The dipole-dipole interaction parameters that drive the non-radiative energy transfer processes depend on doping concentration due to crystallite phase changes. In addition the non-radiative relaxation rate ( 4I11/2→ 4I13/2) is found to be greater than that estimated by the Judd-Ofelt parameters due to the action of surface impurities. Results suggest that non-radiative direct Yb 3+ to Er 3+ energy transfer processes in ZrO 2:Yb,Er are extremely efficient. 相似文献
4.
An Er:Yb:NaCe(WO 4) 2 crystal was grown by the Czochralski method. Spectral properties of the crystal were investigated and compared with those
of the Er:Yb:Ce:NaGd(WO 4) 2 crystal. The green up-conversion was not observed when the Er:Yb:NaCe(WO 4) 2 crystal was excited by a diode laser at 970 nm. The efficiency of energy transfer from Yb 3+ to Er 3+ in the Er:Yb:NaCe(WO 4) 2 crystal was calculated to be about 93%. End-pumped by a diode laser at 970 nm in a hemispherical cavity, 0.95 W quasi-CW
laser at 1.5–1.6 μm was achieved in a 1.47-mm-thick c-cut Er:Yb:NaCe(WO 4){ia2} crystal, the slope efficiency was 11%, and the threshold was 2.83 W. 相似文献
5.
高温熔制Er 3+,Yb 3+离子掺杂CaO-Y 2O 3-Al 2O 3-SiO 2系统玻璃,并进行微晶化处理,研究了微晶玻璃中Er 3+离子的发光及上转换发光特性,分析了微晶玻璃上转换发光机理.结果表明:原始玻璃经热处理得到了Er,Yb:YAG微晶玻璃,微晶玻璃中Er 3+离子在室温下 4I 13/2→ 4I 15/2跃迁产生横盖1450—1650nm区间的超宽带荧光,荧光半高宽达180nm,这可能由于YAG微晶相中Er 3+离子与玻璃相中残留Er 3+离子的共同发光;Er 3+与Yb 3+离子局域基质声子能量的降低使微晶玻璃Er 3+离子上转换发光强度与原始玻璃相比显著提高,绿光、红光上转换荧光强度比玻璃样品分别增强约7和3倍;微晶化后Er 3+,Yb 3+离子局域环境发生变化也导致微晶玻璃中Er 3+离子绿光、红光上转换发光相对强度发生变化.
关键词:
铒
镱:钇铝石榴石
微晶玻璃
荧光光谱 相似文献
6.
The paper is dedicated to the study of the optical properties of YAG:Yb,Er single-crystalline films (SCF) grown by liquid phase epitaxy. The absorption, cathodoluminescence and time-resolved photoluminescence spectra and photoluminescence decay curves were measured for the SCFs with different doping levels of Er 3+ (from 0.6 to 4.2 at.%) and Yb 3+ (from 0.1 to 0.6 at.%). The spectra, excited by synchrotron radiation in the fundamental absorption range of the YAG and in the intraionic absorption bands of both dopants, reveal energy transfer from the YAG host to the Er 3+ and Yb 3+ ions and between these ions. 相似文献
7.
采用固相反应方法,制备了Er 2O 3浓度固定为0.5mol%,Yb 2O 3浓度范围为0.0mol%—5.5mol%的Er/Yb共掺激光玻璃.通过吸收光谱、光致荧光光谱和上转换荧光光谱,研究了Yb 2O 3浓度对Er 3+荧光特性的影响,并探讨了相关的物理机制.研究结果表明:Yb 3+共掺对Er 3+的 4
关键词:
Er/Yb共掺
光致荧光
能量传递
合作上转换 相似文献
8.
We report on the spectroscopy and, for the first time to our knowledge, continuous-wave and Q-switched diode-pumped laser
operation of Er,Yb:YVO 4 crystal. Absorption and emission spectra of the crystal were determined. Lifetimes of Er 3+
4
I
13/2 and 4
I
11/2 levels that define laser performance of the crystal were measured and parameters of energy transfer between Yb 3+ and Er 3+ ions were estimated. cw output power of 115 mW with slope efficiency of 5.4% was achieved at 1604 nm. In the Q-switched mode
an average output power of 81 mW with slope efficiency of 3.5% and pulse duration of 150 ns was obtained. In quasi-cw regime
maximal peak power of 610 mW with slope efficiency of 6.7% was demonstrated.
PACS 42.55.Xi; 42.60.Gd; 42.70.Hj 相似文献
9.
An Er 3+/Yb 3+-codoped Li 6Y(BO 3) 3 crystal was grown by the Czochralski method. The polarized absorption spectra and the fluorescence decay curve were recorded.
The efficiency of energy transfer from Yb 3+ to Er 3+ ions was estimated. Quasi-continuous-wave output power of 325 mW at 1594 nm was realized under the absorbed pump power of
10.4 W in a hemispherical cavity. The absorbed pump threshold and slope efficiency of the laser are 6.0 W and 7.2%, respectively.
PACS 42.55.Xi; 42.70.Hj 相似文献
10.
采用固相法和真空烧结技术制备了5at%Yb 3+,2at%Er 3+:YAG透明陶瓷.在1760 ℃真空烧结30 h后, 陶瓷样品具有较高透过率.SEM观察表明制备的透明陶瓷在晶粒和晶界处无气孔、第二相的存在.样品的吸收光谱和荧光光谱的测试结果表明: Yb 3+在940nm波长处有具有较强的吸收系数.样品在1030nm波长的荧光寿命仅为0.274 ms,以及在1.5μm波段的荧光衰减寿命曲线中,初始的荧光强度呈上升趋势,这些表明了Yb,Er:YA
关键词:
Er
Yb:YAG透明陶瓷
1.5 μm荧光光谱
Judd-Ofelt理论 相似文献
11.
Laser crystal Yb 3+-doped NaY(WO 4) 2 (Yb:NYW) with excellent quality has been grown by Czochralski technique. The rocking curves from (400) plane of as-grown
Yb:NYW crystal was measured and the full-width value at half-maximum was 19.92″. The effective segregation coefficients were
measured by the X-ray fluorescence method. The polarized absorption spectra and the fluorescence spectra of Yb:NYW crystal
were measured at room temperature. The fluorescence decay lifetime of Yb 3+ ion in NYW crystal has been investigated. The spectroscopic parameters of Yb:NYW crystal are calculated and compared with
those of Yb:YAG crystal. A continuous wave output power of 3.06 W at 1031 nm was obtained with a slope efficiency of 42% by
use of diode pumping. 相似文献
12.
Luminescence spectra of gradient-activated LiNbO 3:Yb, Er crystals with predefined concentration profiles of the optical centers are studied in different spectral regions. The process of electronic excitation energy transfer in the Yb 3+–Er 3+ system inside the LiNbO 3 matrix is calculated and dependences of the quantum efficiency of the up-conversion processes for the green and red luminescences of erbium ions on the time of excitation energy deactivation are obtained. 相似文献
13.
The electron-excitation energy transfer between Er 3+ and Yb 3+ ions in Er,Yb:YAl 3(BO 3) 4 crystals has been investigated. Crystals with different concentrations of active ions have been grown, and their luminescence decay kinetics in the spectral range near 1 μm have been experimentally measured. The energy-transfer microparameters have been calculated. It is shown that, to correctly describe the energy transfer in Er,Yb:YAl 3(BO 3) 4 crystals, one must take into account the interactions of higher orders than dipole-dipole interactions. 相似文献
14.
Energy transfer has been studied from Er 3+ to Eu 3+ ions on excitation with NIR photons (796 and 980 nm) with and without Yb 3+ ions. It is found that in one case the presence of Yb 3+ enhances the fluorescence yield (980 nm excitation) whereas in the other case it quenches (796 nm excitation). Energy transfer from Er 3+ ion's levels 4S 3/2 and 2H 11/2 is verified by decay curve analysis in both the cases. The nature of interaction between the donor (Er) and the acceptor (Eu) ions is found to be dipole-dipole. The energy transfer parameters viz. transfer probability, critical distance etc. have been calculated. 相似文献
15.
采用化学共沉淀法制备了系列Y 1.98-2xYb 2x Er 0.02SiO 5(0.00≤ x≤0.15)以及Y 1.736Yb 0.24Er 0.02Tm 0.004SiO 5上转换发光材料,比较了室温下Y 1.98-2xYb 2x Er 0.02 SiO 5 ( x=0.00,0.08)样品在400—1600 nm范围内的吸收光谱,测量了所有样品在976 nm OPO激光器激发下的上转换发射光谱,以及Er 3+离子 4S3/2(4F9/2)→4I15/2,Tm 3+离子 1G4→3H6荧光衰减曲线和不同激发功率下的上转换蓝光发射强度,从而分析讨论了Er 3+,Tm 3+在Y 2SiO 5中的上转换发光机理.研究结果表明:在1250 ℃相对较低的温度下合成了X2型单斜晶系Y 2SiO 5 ∶Ln 3+(Ln 3+=Er 3+,Yb 3+,Tm 3+),Yb 3+的敏化显著增强了样品在976 nm附近的吸收能力,并大幅度加宽了该处的吸收带.分析上转换发射光谱发现:上转换绿光和红光强度都随着Yb 3+浓度的增加先增强后减弱,但红光的猝灭浓度较高,归因于Er 3+→Yb 3+反向能量传递ETU4和Yb 3+→Er 3+正向能量传递ETU3过程的发生;上转换蓝光发射是三光子吸收过程,是通过Yb 3+,Tm 3+之间三次声子辅助的能量转移方式实现的.
关键词:
上转换
共沉淀
2SiO 5∶Er 3+')" href="#">Y 2SiO 5∶Er 3+
3+')" href="#">Yb 3+
3+')" href="#">Tm 3+ 相似文献
16.
Yb 3+-doped NaGd(WO 4) 2 (Yb:NGW) crystal has been successfully grown by Czochralski method. The rocking curves from (400) plane of as-grown Yb:NGW
crystal was measured and the full-width values at half-maximum was 21″. The polarized absorption spectra, the fluorescence
spectra and the fluorescence decay lifetime of Yb:NGW crystal were measured at room temperature. The spectroscopic parameters
of Yb:NGW crystal are calculated and compared, with those of Yb:YAG crystal. A continuous wave output power of 3.01 W at 1048
nm was obtained with a slope efficiency of 71% by use of diode pumping. 相似文献
17.
The LuVO 4:Er single crystals were grown by the Czochralski technique. The crystal-field split energy levels of Er 3+ ion were derived experimentally employing absorption and emission spectra measured at T=10 K. The Judd–Ofelt phenomenological method was used to estimate intensity parameters, radiative lifetimes and branching ratios of luminescence. The excited state dynamics of the LuVO 4:Er systems was investigated and experimental lifetimes of emitting levels were measured. The emission cross section of the 4I 13/2→ 4I 15/2 transition in the infrared was calculated by the Füchtbauer–Ladenburg method. The gain cross section, estimated for several inverse-population parameters, allowed us to evaluate a potential laser activity of the LuVO 4:Er system at 1.6 μm. Also, the potential range of the optical pumping was assessed based on absorption spectra achieved at the room temperature. The optical losses related to the green up-converted emission, encountered under the 978 nm excitation between 300 and 670 K were indicated and discussed. Spectroscopic peculiarities of the Er 3+-doped LuVO 4 crystal were discussed in relation to optical properties of the YVO 4:Er and GdVO 4:Er crystals. Taking into account the high quantum efficiency of the 4I 13/2 level, and satisfactory absorption and emission features, the LuVO 4:Er crystal can be considered as a promising active material for laser operation near 1.6 μm. 相似文献
18.
Crystalline structures and infrared-to-visible upconversion luminescence spectra have been investigated in 1 mol% Er 3+, 10 mol% Yb 3+ and 0-20 mol% Li + codoped TiO 2 [1Er10Yb(0-20)Li:TiO 2] nanocrystals. The crystalline structures of 1Er10Yb(0-20)Li:TiO 2 were divided into three parts by the addition of Yb 3+ and Li +. Both green and red upconversion emissions were observed from the 2H 11/2/ 4S 3/2 → 4I 15/2 and 4F 9/2 → 4I 15/2 transitions of Er 3+ in Er 3+-Yb 3+-Li + codoped TiO 2, respectively. The green and red upconversion emissions of 1Er:TiO 2 were enhanced significantly by Yb 3+ and Li + codoping, in which the intensities of green and red emissions and the intensity ratio of green to red emissions ( Igreen/ Ired) were highly dependent on the crystalline structures. The significant enhanced upconversion emissions resulted from the energy migration between Er 3+ and Yb 3+ as well as the distortion of crystal field symmetry of Er 3+ caused by the dissolving of Li + at lower Li + codoping concentration and the phase transformation at higher Li + concentration. It is concluded that codoping with ions of smaller ionic radius like Li + can efficiently improve the upconversion emissions of Er 3+ or other rare-earth ions doped luminsecence materials. 相似文献
19.
The spectroscopic properties and energy transfer mechanisms in Ho 3+ doped fluorophosphate glasses sensitized by Er 3+ and Tm 3+ at the 2 μm region are investigated. The absorption spectra and fluorescence spectra of the Tm–Ho doubly-doped glass system and Er–Tm–Ho triply-doped glass system are measured. According to the absorption spectra, the Judd–Ofelt parameters and spontaneous transition probability are calculated and compared with those of other glass hosts. From the fluorescence spectra, the fluorescence intensity of Er–Tm–Ho glass system at 2.0 μm is 0.95 and larger than that of the Tm–Ho glass system, which is 0.69. Meanwhile, the 2.0 μm to 1.8 μm and 2.0 μm to 1.53 μm peak intensity ratios in the Er–Tm–Ho glass system are 8.63 and 22.79, respectively, suggesting sufficient energy transfer between Er 3+, Tm 3+ and Ho 3+ ions. In addition, the pumping schemes and energy transfer mechanisms of Tm–Ho doubly-doped and Er–Tm–Ho triply-doped glasses are discussed. The study indicates that the Er–Tm–Ho triply-doped glass system is a significant sensitized way pumped at 800 nm in fluorophosphate glasses for 2 μm applications. 相似文献
20.
Sensitization of the fluorescence of Er3+ in fluoride phosphate glass containing up to 20 mol% phosphates by codoping with Cr3+ and Yb3+ is shown. The low order of ligand field strength for Cr3+ (Dq/B=2.04) results in broad Cr3+ fluorescence overlapping the Yb3+ absorption. The electronic energy transfer efficiency approaches 100%. Deviations of donor decay from the Förster law are interpreted in terms of the inhomogeneously acceptor distribution. The electronic energy transfer efficiency of Yb3+ → Er3+ reaches a maximum value of 75% for glasses containing 20 mol% phosphates. The transfer is shown to be migrationally accelerated by means of GAF-LAF-FB theory. From Judd-Ofelt parameters a stimulated emission cross-section for the transition4I13/2 →4I15/2 of Er3+ of 6.2×10−20 cm2 is derived. The c.w. laser action of Er3+ by Cr3+ excitation and double-step energy transfer is shown. The output is tuned continuously from 1536 to 1596 nm. Flashlamp pumping is also shown. 相似文献
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