掺杂Er3+的Ti02的发射光谱研究

用无水乙醇、冰醋酸、钛酸丁酯凝胶法制备了掺Er3 的TiO2粉末,测量了其在488 nrn激发下?栽 的Stokes发射光谱和980 nm激发下的上转换发光光谱.在可见光范围内,观察到了绿光和红光,绿光从500～570 nm,对应Er3 的2H11/2,4S/2→4I15/2,红光从650～690 nm,对应Er3 的4F9/2→4I15/2的跃迁.由ln Ivis-ln Iin曲线可知,绿光和红光均为双光子过程,光强正比于泵浦功率的二次方,即Iout∝Iin.初步研究了此材料的上转换过程.     

Yb^3＋/Er^3＋掺杂氟氧化物微晶玻璃的制备与发光性能

采用高温熔融法制备了Yb3＋/Er3＋掺杂的氟氧化物发光微晶玻璃,确定了最佳熔化温度（1 100℃）和退火温度（440℃,480℃）。测定得到基质玻璃的透过率为85%,掺入稀土后,透过率有所下降,并出现了稀土离子的特征吸收峰。980 nm半导体激光器（LD）激发下样品的上转换发射光谱存在4个明显的发射峰,分别为410,532,546和656 nm,对应于2H9/2→4I15/2,2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2跃迁。研究了不同Yb3＋/Er3＋（摩尔分数）和Er3＋浓度对上转换发光强度的影响,当Yb3＋∶Er3＋=4∶1、Er3＋摩尔分数为1.5%时,上转换发光强度达到最高。根据发光强度与泵浦功率之间的关系,确定了上转换发射均为双光子过程。讨论了Yb3＋,Er3＋离子间的能量传递,建立了上转换发光机制。     

Structural and Luminescence Properties of Transparent Nanocrystalline ZrO2：Er^3＋ Films

The structural and luminescence properties of nanocrystalline ZrO2 ：Er^3＋ films are reported. Transparent nano-ZrO2 crystalline films doped with Er^3＋ have been prepared using a wet chemistry process. An intense roomtemperature emission at 1527nm with a full width at half-maximum of 46 nm has been observed, which is assigned to the ^4Ⅰ13/2 → ^4Ⅰ15/2 intra-4f^n electric transition of Er^3＋. Correlations between the luminescence properties and structures of the nanocrystalline ZrO2 ：Er^3＋ films have been investigated. Infrared-to-visible upconversion occurs simultaneously upon excitation of a commercially available 980-nm laser diode and the involved mechanisms have also been explained. The results indicate that the nanocrystalline ZrO2：Er^3＋ films might be suggested as promising materials for achieving broadband Er^3＋-doped waveguide amplifiers and upconversion waveguide lasers.     

Er^3＋ and Yb^3＋ Codoped Phosphate Laser Glass for High Power Flashlamp Pumping

A novel yb^3＋-Er^3＋ codoped phosphate glass for high power flashlamp pumping and high repetition rate laser at 1.54μm, designated EAT5-2, is developed. The weight-loss rate of is 1.3 × 10^-5 gcm^-2h^-1 in boiling water, which is comparable to Kigre＇s QX-Er glass. Some spectroscopic parameters are analysed by Judd-Ofelt theory and McCumber theory. The emission cross section is calculated to be 0.73 × 10^-20 cm^2. The thermo-mechanical properties of EAT5-2 are modified after an ion-exchange chemical strengthening process in a KNO3/NaNO3 molten salt bath. The thresholds for optical damage from the flashlamp pumping are tested on glass rods. A repetition rate of 15 Hz is achieved for chemically strengthened glass. The laser experimental results at 1.54 μm from flashlamp pumping are also reported.     

Upconversion properties of Er^3＋/Yb^3＋ co-doped TeO2-Nb2O5-Li2O glasses

The Er^3＋/Yb^3＋ co-doped TeO2-Nb2O5-Li2O glass is prepared by conventional melting method, and its upconversion spectra are measured. The intense green upconversion luminescence upon excitation with a 976 nm laser diode is observed with the naked eyes. The dependence of luminescence intensity on the ratio of Yb^3＋/Er^3＋ is discussed in detail, and the relationship between the ratio of green luminescence intensity to red luminescence intensity and the ratio of Yb^3＋/Er^3＋ is also studied, The luminescence intensity increases with the ratio of Yb^3＋/Er^3＋ increasing. The ratio of Yb^3＋/Er^3＋ plays a more important role than the concentration of Er^3＋ in determining the upconversion luminescence intensity. The ratio of green luminescence intensity to red luminescence intensity reaches a maximum when ratio of Yb^3＋/Er^3＋ is 3. Thus the glass could be one of the potential candidates for LD pumping solid-state lasers.     

UV and visible upconversion luminescence in Er^3＋：YAG under red laser excitation

This paper reports that the ultraviolet and visible upconversion luminescence from the ^4S3/2, ^2G9/2 and ^2P3/2 levels have been observed in Er^3＋：YAG following 647.2 nm excitation of the ^4F9/2 multiple. Upconversion luminescence intensity dependence on pump power was recorded. The measured decay profiles were theoretically fitted by kinetics theory and the basically good agreements were achieved. The results indicate that some energy transfer processes proposed to explain the observed upconversion phenomena are reasonable.     

掺Er^3＋离子Sr3Y2（BO3）4晶体光谱性能的研究

研究了提拉法生长的掺Er^3＋的Sr3Y2（BO3）4晶体的吸收光谱和荧光光谱。应用J—O理论分析并计算了光谱参数,得到唯象参数Ω2、Ω4和Ω6分别为11．90×10^-20cm^2、3．44×10^-20cm^2和1．92×10^-20cm^2。在Er^3＋：Sr3Y2（BO3）4晶体中,Er^3＋在1533nm波长的发射截面为1．00×10^-20cm^2,^4I13／2→^I15／2能级跃迁的荧光寿命和辐射寿命分别为0．58ms和4．10ms,良好的光谱性能表明Er^3＋：Sr3Y2（BO3）4晶体可能成为潜在的1．55μm波段的一种激光材料。     

Er^3＋/Yb^3＋ Codoped Phosphate Glass Fibre with Gain per Unit Length Greater Than 3.0 dB/cm

We experimentally study a novel fibre with high gain per unit length based on the homemade erbium-ytterbium codoped phosphate glass. The gain and noise characterizations with different pump powers at different wavelengths are investigated. The 1.8-cm-long fibre, dual-pumped by two single mode 980-nm fibre-pigtailed laser diodes, provides a gain per unit length greater than 3.0dB/cm and a noise figure less than 6.SdB. The gain saturation behaviour at 1535nm is obtained and the saturation output power （3 dB compression） is greater than 5 dBm.     

Upconversion Luminescence Dynamics in Er^3＋/Yb^3＋ Codoped Nanocrystalline Yttria

The upconversion luminescence and dynamics in Er^3＋ /Yb^3＋ codoped nanocrystalline yttria （7-65 nm） are studied under 980-nm pulsed laser excitation, It is found that the red emission of ^4F9/2-^4I15/2 and the green emission of ^2H11/2/^4S3/2 in nanoparticles with lower concentration of Yb^3＋ result from a two-photon excitation, In nanocrystals with higher Yb^3＋ concentration, the red emissions from a two-photon excitation, while the green emissions from a three-photon excitation, The luminescence dynamics indicates that as the particle size decreases, both the rise and the decay time constants become shorter, As the size decreases to several nanometres, the rise process nearly disappears, suggesting that the upconversion luminescence originates mainly from self-excitation of Er^3＋, instead of the energy transfer of Yb^3＋→ Er^3＋.     

980 nm激光泵浦下掺Er3+碲酸盐玻璃的光子雪崩上转换

在980 nm激光二极管的抽运下,掺Er3 碲酸盐玻璃辐射出很强的绿色上转换荧光,荧光强度与抽运功率呈非线性关系,发光强度和积累时间与激光抽运功率的关系研究表明存在雪崩阈值44 mW.发现光子的积累时间(几十毫秒量级)远大于荧光的寿命,且积累时间随抽运功率的增大而减小.与早先报道的690和579 nm抽运波长相比,980 nm是更加有效的抽运波长.     

YLiF4: Er3+, Tm3+, Yb3+中Tm3+浓度对上转换发光的影响

利用水热法合成了YLiF4: Er3 , Tm3 , Yb3 , 其中Er3 和Yb3 的浓度保持固定不变, 分别为1 mol%和1.5 mol%, Tm3 浓度变化范围是2 mol%～8 mol%. 在这种共掺杂体系中, 同时观察到了Er3 , Tm3 和Yb3 的吸收, 且Tm3 的吸收随着其浓度的增强而增强. 在980 nm光的激发下, 当Tm3 浓度很小时, 这种材料的上转换发光为白光. 其中蓝光主要来源于Tm3 的激发态1G4到基态3H6的跃迁, 绿光来源于Er3 的4S3/2和2H11/2到基态4I15/2的跃迁, 红光既来源于Tm3 的1G4→3F4的跃迁, 也来源于Er3 的4F9/2→4I15/2的跃迁. 并且这种上转换发光强度随着Tm3 浓度的增强而降低, 但对应不同能级跃迁的发光强度降低的幅度不同, 这是因为Er3 和Tm3 之间的相互作用.     

氧化物纳米材料Y2O3:(Yb3+,Er3+)上转换发光性质的研究

以Y2O3,Yb2O3,Er2O3为原料,利用燃烧法分别制备了Y2O3:Er3 和Y2O3:(Yb3 ,Er3 )两种纳米材料和相应的体材料Y2O3:(Yb3 ,Er3 ).用发射波长为978 nm的半导体激光器和日立F-4500荧光分析仪测量了它们的上转换发光,得到纳米材料Y2O3:Er3 的上转换发光主要为绿色上转换发射而纳米材料Y2O3:(Yb3 ,Er3 )主要为红色上转换发射,而后者与激活离子掺杂浓度相同的体材料Y2O3:(Yb3 ,Er3 )的上转换发射相比较,体材料以绿色上转换发射为主、红色上转换发射很弱.     

Er3+/Yb3+共掺杂纯氧化物材料上转换发光特性的研究

对实验制备的Er3 /Yb3 共掺杂3CaO-Al2O3-3SiO2样品在980激发下的上转换发光特性进行了研究, 检测到由处于激发态能级2H11/2, 4S3/2和4F9/2的Er3 离子分别向基态4I15/2跃迁时发出的波长依次为523, 547和656 nm的上转换发光. 做出了上转换发光强度与激发功率关系的曲线图, 并结合测得的声子能量对相应跃迁机制进行了分析, 发现上转换过程中Yb3 对的敏化作用起主要作用.     

掺Er3+玻璃的光限幅特性研究

利用波长为532 nm的皮秒脉冲激光,研究了掺Er3 玻璃的光限幅特性和反饱和吸收.当入射功率不断增加且超过一定阈值时,透射功率不再随着入射功率快速增大,而是逐渐趋向于较稳定状态,从而实现了对强激光的光限幅效应.进一步利用布居速率方程讨论了其机制并给出了激发态的吸收截面,结果表明激发态吸收是其主要的光限幅机理.     

Yb3+/Er3+共掺杂TeO2-WO3-ZnO玻璃的光谱性质

制备了Yb³⁺/Er³⁺共掺杂的TeO₂-WO₃-ZnO玻璃,测量了Er³⁺在玻璃中的吸收光谱和970nmLD激发下的荧光光谱、荧光寿命和上转换光谱.计算了Yb³⁺/Er³⁺间的能量传递效率和Er³⁺离子1.5μm波段的吸收截面、发射截面,并研究了其荧光强度和上转换发光与Yb³⁺掺杂浓度间的关系.结果表明,Yb³⁺共掺杂可明显提高Er³⁺离子1.5μm发射的荧光强度,实验所得Yb³⁺离子的最佳掺杂浓度为Er³⁺离子浓度的3倍,在7.28×1020ions/cm³左右.Er³⁺离子1.5μm发射的荧光半峰全宽为67～72nm;上转换红、绿光均为双光子过程,随Yb³⁺掺杂浓度的增加,上转换红、绿光强度均增强.     

铒离子浓度对掺Er3+碲酸盐玻璃的Judd-Ofelt理论参数的影响

制备了四种不同铒离子掺杂浓度的碲酸盐玻璃,通过测定吸收光谱计算了吸收谱线的振子强度,根据Judd-Ofelt理论计算了不同浓度下Er3 离子发光光谱的强度参数Ωi(i=2,4,6),计算了自发辐射电偶和磁偶跃迁概率、辐射寿命、荧光分支比等参数,讨论了Er3 离子浓度变化对以上这些参数的影响.测试了Er3 :4I13/2→4I15/2跃迁对应的荧光光谱和Er3 :4I13/2能级荧光寿命.最后应用McCumber理论计算了玻璃中Er3 :4I13/2→415/2跃迁对应的受激发射截面大小.结果表明:振子强度基本上随Er3 离子浓度的增大而增强;随着Er3 离子浓度的增加,自发辐射跃迁概率A基本呈现出递增的趋势,但荧光分支比β却只有很小的变化;Er3 :4I13/2→4I15/2的发射截面随Er3 离子浓度的增大而改变很小,有效线宽都在50 nm左右.     

掺Er3+钆硼硅酸盐玻璃及玻璃陶瓷的红外发光特性和热稳定性

报道了一种新型可作为掺铒光纤放大器(EDFA)基质材料的Er³⁺掺杂B₂O₃-SiO₂-Gd₂O₃-Na₂O(BSGN)体系玻璃及其玻璃陶瓷。对材料中铒的⁴I_13/2→⁴I_15/2跃迁的1.5μm发射光谱、吸收光谱、时间分辨光谱及寿命进行了测量和分析,讨论了热处理对玻璃材料带宽和寿命的影响。结果表明,铒掺杂玻璃1.5μm发射的带宽和J-O参数Ω₆都随B₂O₃含量的增加而增加,寿命随B₂O₃含量的增加而减小。经过热处理后得到的玻璃陶瓷比具有相同组分的玻璃具有更高的1.5μm发射效率。同时,差热分析的数据表明,该玻璃体系具有极好的热稳定性。     

Er3+/Yb3+/Tm3+共掺杂氟化物中红色上转换发光研究

氧化铒的质量增加到原来的10倍左右时发现两种配方的发光性质有明显不同。根据情况作研究了Er^3 ／Tm^3,Er^3 ／Er^3-和Er^3 ／Yb^3 /Tm^3 发光系统在980nm抽运下的荧光光谱和上转换发光的性质,以及在声子能量较低的氟化物中,3个发光系统建立的优先性和Er^3 离子浓度的关系。根据实验发现当Er^3 离子浓度由小逐渐变大时,绿光和红光的强弱比例也有明显的变化。其中作认为起决定性作用的是Er^3 离子浓度。因为在均匀体系中每个稀土离子的和另一个稀土离子的结合形成发光系统的机会是平等的,组成发光系统的稀土离子间的距离变化,即其中一种起决定作用的离子浓度变化时,那么它所组成的发光系统也就相应发生变化(稀土离子的优先结合性也会在此得到体现),从而发出的主色的光也就跟着变化。