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采用溶剂挥发法,在室温条件下生长出掺不同浓度Mn4+的K2TiF6∶Mn4+红光晶体。样品在紫光区和蓝光区都表现出Mn4+的特征宽带激发,对应于其4A2→4T1和4A2→4T2能级跃迁。在蓝光激发下,所有晶体都呈现出一系列窄带红光发射,其中最强发射峰位于631 nm处。在这些晶体中,样品K2TiF6∶Mn4+(13.18%)表现出最高效的红光发射,其内外量子效率分别高达97.2%和83.3%。值得一提的是,该样品表现出荧光负热猝灭效应,其在120℃时的红光发射强度是室温时的1.81倍。所得晶体与Y3Al5O12∶Ce3+(YAG∶Ce3+ 相似文献
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采用高温固相法制备了Na2SrMg(PO4)2: Ce3+, Mn2+ (NSMP: Ce3+, Mn2+) 荧光粉, 并对其发光性质及Ce3+ 对Mn2+ 的能量传递机理进行了研究. Ce3+ 和Mn2+ 在334 nm 和617 nm 的发射峰分别为Ce3+ 的5d→4f 跃迁和Mn2+ 的4T1(4G)→6A1(6S) 跃迁产生. Ce3+ 对Mn2+ 的发光有较强的敏化作用, 根据Dexter能量传递效率公式判断Na2SrMg(PO4)2 中Ce3+ 对Mn2+ 的能量传递属于电偶极-电四极相互作用引起的共振能量传递. 相似文献
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采用提拉法生长出了钕掺杂钪酸钆晶体(Nd3+:GdScO3),通过低温吸收光谱和室温发射光谱,对其中Nd3+的实验能级进行分析指认,确定了Nd3+:GdScO3的66个实验Stark能级,拟合了其自由离子参数和晶体场参数,拟合均方根误差为13.17 cm-1.与Nd3+:YAP和Nd3+:YAG相比, Nd3+:GdScO3的晶场强度较弱.弱的晶体场强度有可能是Nd3+:GdScO3晶体具有优良激光特性的原因之一.本文数据集可在https://www.doi.org/10.57760/sciencedb.15702中访问获取. 相似文献
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用高温固相反应法合成了Ba2SiO4:xCe3+,yMn2+(x=0~0.2, y=0~0.15)荧光粉,研究了荧光粉的晶体结构和发光性质。在紫外光激发下,Ba2SiO4:xCe3+的发射光谱为位于384 nm附近的宽带。Ba2SiO4:Mn2+样品的发射光谱位于376 nm的宽带较强,红光发射极弱。在Ce3+和Mn2+共掺的Ba2SiO4:xCe3+,yMn2+样品中,位于606 nm附近的红光发射较强,来源于Mn2+的4T1(4G)-6A1(6S)跃迁。这说明Ce3+离子将部分能量传递给了Mn2+离子,有效地敏化了Mn2+离子的发光。当Ce3+的摩尔分数为0.2、Mn2+的摩尔分数为0.075时,Ba2SiO4:xCe3+,yMn2+荧光粉位于606 nm的Mn2+的发射峰最强。 相似文献
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采用高温固相法,制得一种新型荧光粉Na4Ca3(AlO2)10∶Eu2+,Mn2+。样品的结构和发光性质分别由X射线衍射谱和荧光光谱来表征。在Na4Ca3(AlO2)10∶Eu2+的激发光谱中出现了Eu2+的f-d跃迁吸收带;在发射光谱中,出现蓝光发射,峰值位于441 nm。当在Na4Ca3(AlO2)10∶Eu2+中掺杂Mn2+时,发生了Eu2+→Mn2+的能量传递,在542 nm处出现了Mn2+的发射峰。在Na4Ca3(AlO2)10∶Eu2+,Mn2+中,随着Mn2+浓度的增加,Eu2+粒子的发射强度减弱,而Mn2+粒子的发射强度增强,且Eu2+离子发射的衰减时间缩短,同时色度由蓝光移向白光。 相似文献
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通过拉曼散射光谱,吸收光谱,荧光发射寿命和808 nm LD激发下的红外荧光光谱的实验测量,系统研究了Nd3+:SrMoO4晶体的自受激拉曼光谱性质.分析指认了拉曼散射光谱中各拉曼峰所对应的晶格振动模式,得出了其SRS活性最强的声子频率约为898 cm-1,对应于(MoO2-4)离子团的完全对称光学伸缩振动Ag模;通过J-O理论对晶体的吸收谱进行了全面的光谱参数计算,得出4F3/2→4I11/2跃迁的积分发射截面达0.57×10-18 cm2,自发辐射概率为141.06 s-1;同时,实验测得该跃迁的荧光发射寿命约为0.2 ms.最后,结合808 nm LD激发下的红外波段荧光光谱,论证了SrMoO4晶体中Nd3+离子1068 nm发射通过拉曼频移获得1180 nm一级斯托克斯激光发射的可能性,为Nd3+:SrMoO4晶体的自受激拉曼激光器研究提供了理论依据.
关键词:
3+离子')" href="#">d3+离子
4 晶体')" href="#">SrMoO4 晶体
自受激拉曼散射 相似文献
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The excitation spectrum of the Mn2+ emission has been measured in CaF2 and CdF2. The observed excitation bands have been assigned to transitions of the Mn2+ ions in a cubic environment. The calculated values for the crystal field (Dq) and Racah parameters (B,C) are Dq = 425 cm-1 for CaF2, Dq = 500 cm-1 for CdF2 and, B = 770 cm-1 and C / B = 4.48 for both compounds. The lifetime of the fluorescent level 4T1g(4G) has been measured in both compounds at different temperatures in the range from 10 to 500 K. The lifetime thermal dependence is explained taking into account different mechanisms (purely radiative, phonon assisted, and radiationless transitions) for the decay of excited Mn2+ ions. 相似文献
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M. Sekita 《Journal of luminescence》1981,22(4):335-347
The emission and excitation spectra of the Bi2Ge3O9:Eu crystal are observed at 77 K and 297 K. The spectra contain groups of sharp lines which are attributed to the transitions within 4f6 (Eu3+) configuration. The numbers of Stark splitting of terminal levels of transitions from 5D0 and 7F0 multiplets indicate that Eu3+ substitutes for Bi3+ in Bi2Ge3O9. Tentative assignment of Stark levels of 7F0-4 multiplets is made to crystal quantum numbers of C3 symmetry which represents the site symmetry of Bi3+ in Bi2Ge3O9. The following set of values of crystal field parameters of the C3 point group is found to give the best overall agreement between the observed energy levels and the calculated levels: B20 = -533.84 cm-1, B40 = 1085.99 cm-1, Re(B43) = 327.57 cm-1, Im(B43) = 75.209 cm-1, B60 = 185.02 cm-1, Re(B63) = - 68.475 cm-1, Im(B63) = - 300.45 cm-1, Re(B66) = 137.24 cm-1 and Im(B66) = 882.29 cm-1. 相似文献
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W. Wardzyński H. Szymczak M.T. Borowiec K. Pataj T. Łukasiewicz J. Żmija 《Journal of Physics and Chemistry of Solids》1985,46(10):1117-1129
The optical absorption and ESR spectra of Bi12GeO20 and B12SiO20 doped with Mn have been measured before and after illumination with visible light. Uniaxial stress measurements on a sharp line observed at 8026 cm?1 were performed. The observed ESR spectrum is a superposition of six lines resulting from the hyperfine interaction of manganese ions in tetrahedral positions. The g-factor and hyperfine constant are g = 1.999 ± 0.003 and A = 78 Gs. Analysis of the light-induced absorption spectrum leads to the conclusion that a small hole polaron bound to an Mn impurity at a tetrahedral site is responsible for the very broad absorption band which appears after illumination. The sharp line is interpreted as due to a transition inside the Mn+ center in tetrahedral coordination. Bands in the region 10,000–16,000 cm?1 are due to Mn3+ centers in interstitial positions, whose symmetry can be treated to a first approximation as tetragonal. The following crystal field parameters for this center were found: B = 565 cm?1, Dq = 1400 cm?1, Dt = ?330 cm?1, Ds = 4170 cm?1 and C = 2260 cm?1. The illumination conditions which are needed for homogeneous coloration of the sample are also discussed. 相似文献
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Low frequency modes were observed in a series of alkali halides doped with lead after X-irradiation at 77K. The peak positions of the Raman signals are at 34cm-1 for NaCl:Pb2+, 30cm-1 for KCl:Pb2+,28cm-1 for RbCl:Pb2+ and 22cm-1 for KBr:Pb2+. They are assigned to the inelastic light scattering caused by the local vibration of X-i (Pb+) center, which consists of an interstitial halogen ion stabilized by a substitutional ion Pb+ . Polarized Raman measurements and Behavior Typer(BT) analysis show that the symmetry of the X-i (Pb+) center belongs to the point group C3v A structure model of the X-i (Pb+) center is proposed based on the Raman data and the result of BT analysis. 相似文献
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A comparative study concerning the electronic structure of the Mn5+ ion in the Li3PO4, Ca2PO4Cl, Sr5(PO4)3Cl host lattices has been carried out in the framework of the exchange charge model. The crystal field parameters have been evaluated using the structural data as the only input information. The 10 K absorption spectra of the investigated compounds have been measured in order to verify the correspondence between experimental and calculated energy levels. A systematic trend of the crystal field splitting of the most intense transitions has been evidenced and discussed by considering the symmetry properties of the coordination polyhedra around Mn5+. 相似文献
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I. S. Golovina B. D. Shanina I. N. Geifman A. A. Andriiko L. V. Chernenko 《Physics of the Solid State》2012,54(3):551-558
The electron paramagnetic resonance spectra of KTaO3: Mn nanocrystalline powders in the temperature range from 77 to 620 K have been measured and studied for the first time.
The change observed in the spectra has been investigated as a function of the doping level. The doping regions in which Mn2+ ions are individual paramagnetic impurities have been established, as well as the regions where the dipole-dipole and exchange
interactions of these ions begin to occur. The spin-Hamiltonian constants for the spectrum of non-interacting individual Mn2+ ions have been determined as follows: g = 2.0022, D = 0.0170 cm−1, and A = 85 × 10−4 cm−1. A significant decrease in the axial constant D in the KTaO3: Mn nanopowder, as compared to the single crystal, has been explained by the remoteness of the charge compensator from the
paramagnetic ion and by the influence of the surface of the nanoparticle. It has been assumed that the Mn2+ ions are located near the surface and do not penetrate deep into the crystallites. 相似文献
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Seven absorption group-bands (1D2, 1G4, 3F2, 3F3, 3H4, 3H5, 3F4) of Tm3+ in YVO4 single crystals have been observed in the orientation absorption spectra recorded in the spectral range from 200 to 4000 nm at 300K. The integrated absorption cross section for each group-band was accurately evaluated. On the assumption that the anisotropy of this uni-axial crystal is small, the Judd-Ofelt theory was extended for the calculation of 4f-4f transition intensities of Tm3+ in YVO4. Two sets of phenomenological intensity parameters were derived from a least-squares-fit procedure. For c-axis cut sample we have Ω2=10.18 (10-20cm2), Ω4=1.96 (10-20cm2), Ω6=0.75 (10-20cm2).For a-axis cut sample we have Ω2=8.20 (10-20cm2), Ω4=2.47 (10-20cm2), Ω6=0.91 (10-20cm2). The anisotropy of the optical absorption intensities of Tm3+:YVO4 was theoretically analyzed in detail. 相似文献
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Attempts were made to grow CeO2 and ThO2 single crystals doped with transition metal ions. Only Fe3+ and Mn2+ could be detected by the EPR technique. The EPR spectrum of Fe3+ in CeO2 exhibits the well-known fine structure in cubic fields. The parameters areg=2.0044(1) anda=15.6(1)·10?4 cm?1. The hyperfine constantA for57Fe in hexahedral coordination was found to be 8.9(1)·10?4 cm?1. The EPR spectrum of Mn2+ in CeO2 reveals two cubic Mn2+ centers. The parameters for center 1 areg=1.9999(1) andA=86.9(1)·10?4 cm?1 and for center 2g=1.9984(1) andA=87.0(1)·10?4 cm?1. Heating the Mn doped CeO2 samples in hydrogen, the Mn2+ centers transform from cubic into trigonal centers with approximate values ofg=1.9988(2),A=84.5(6)·10?4 cm?1 andD=203(1)·10?4 cm?1. The two observed Mn2+ centers in ThO2 exhibita priori axial symmetry with approximate values ofg=2.0006(2),A=88.9(4)·10?4 cm?1 andD=33(3)·10?4 cm?1. 相似文献