Er3＋ ion concentration effect on transient and steady-state behavior in Er3＋ ：YAG crystal

The effect of Er3＋ ion concentration on transient and steady-state behavior in 45-nm Er3＋ ：YAG crystal is investigated. It is shown that by changing the signal field, the coherent field and the concentration of Er3＋ ions in the crystal, the absorption, dispersion, and group index of the weak probe field can be adjusted. Also, it is found that the probe absorption occurs in the presence of population inversion and probe amplification is obtained in the absence of population inversion.     

Er3+及Er3+/Yb3+掺杂ZrO2-Al2O3的制备及发光性质

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⁺）.     

Upconversion Luminescence of SrTiO3:Er3+ Ultrafine Powders Produced by 785 nm Laser

以NaCl熔盐法制备了Er3+掺杂的SrTiO3超细粉末. 用X射线衍射、场发射扫描电镜和傅立叶红外光谱研究了SrTiO3:Er3+的结构性质. 测量了514.5 nm激光激发下样品的Stokes荧光谱. 在785 nm激光激发下,观测到很强的绿色和红色上转换发光. 通过研究上转换发光的激发光功率依赖关系、Er3+浓度依赖关系,研究了上转换发光机理. 指出了可能的激发态吸收过程和能量传递过程. 上转换发光性质表明SrTiO3:Er3+超细粉末可用做上转换荧光粉.     

Spectroscopic properties and mechanism of Tm^3＋/Er^3＋/Yb^3＋ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals

Transparent Tm^3＋/Er^3＋/yb^3＋ co-doped oxyfluorogermanate glass ceramics containing BaF2 nanocrystals are prepared. Under excitation of a 980-nm laser diode （LD）, compared with the glass before heat treatment, the Tm^3＋/Er^3＋/yb^3＋ co-doped oxyfluorogermanate glass ceramics can emit intense blue, green and red up-conversion luminescence and Stark- split peaks; X-ray diffraction （XRD） and transmission electron microscope （TEM） results show that BaF2 nanocrystals with an average diameter of 20 nm are precipitated from the glass matrix. Stark splitting of the up-conversion luminescence peaks in the glass ceramics indicates that Tm^3＋, Er^3＋ and （or） Yb^3＋ ions are incorporated into the BaF2 nanocrystals. The up-conversion luminescence intensities of Tm^3＋, Er^3＋ and the splitting degree of luminescence peaks in the glass ceramics increase significantly with the increase of heat treat temperature and heat treat time extension. In addition, the possible energy transfer process between rare earth ions and the up-conversion luminescence mechanism are also proposed.     

掺铒光纤非线性折射率的理论研究

建立了掺杂光纤折射率的普适公式，并利用激光运动方程，推导出折射率随泵浦光强的变化关系，给出了在典型参数下的折射率－光功率变化曲线。发现，在激光中心频率１．５３μｍ附近，当泵浦光强远大于泵浦阈值时，掺铒光纤折射率变化量在１０＾－７量级，这比在相同泵浦光克尔效应引起的变化大３０倍左右，并且这一变化量存在极限，这一极限由掺铒光纤的特性参数唯一确定。     

Yb3+和Er3+共掺杂的CaF2纳米晶近紫外上转换发光

研究了Er³⁺和Yb³⁺共掺杂的CaF₂纳米材料的制备及其紫外上转换发光性质。在980 nm二极管激光器激发下,该材料可发出相对较强的紫外和绿色双色上转换发光。研究了敏化离子Yb³⁺以及发光中心离子Er³⁺掺杂量对该材料紫外上转换发光相对强度的影响,并进一步对该材料紫外上转换发光增强的可能机制进行了探讨。     

Er：YLF晶体中Er^3＋离子的光谱特征

利用居地－奥非脱（Ｊｕｄｄ－Ｏｆｅｌｔ）理论计算了Ｅｒ＾３＋离了在氟化钇锂（ＬｉＹＦ４简写为ＹＬＦ）晶体中的辐射跃迁几率Ａｊｊ无辐射跃迁几率ωＪＪ及激发态荧光寿命τ，并根据荧光动力学方程计算出各激发态布居数ＮＪ与掺杂浓度ｘ的关系，对２．７μｍ激光（＾４Ｉ１１／２→＾４Ｉ１３／２）来说，掺杂浓度要大于～３ａｔ％，才能实现布居数反转，对波长为１．７３μｍ的＾４Ｉ１３／２→＾４Ｉ１５／２跃迁，存在荧光强     

Er3+，Er3+/Yb3+掺杂氟化镧超微材料的光谱特性与上转换发光

采用共沉淀法制备了Er³⁺掺杂和Er³⁺/Yb³⁺共掺杂LaF₃超微材料,所制备的样品的颗粒呈球形,尺寸为250nm左右.计算得到Er³⁺单掺杂样品中对应着⁴S_3/2和⁴F_9/2能级的发光量子效率分别为67.0%和71.9%.研究发现,随着Yb³⁺离子浓度的增加 关键词： 3+')" href="#">Er³⁺ 3+')" href="#">Yb³⁺ 发光 能量传递     

YAG晶体中Cr~（3＋）→Tm~（3＋），Er~（3＋）→Tm~（3＋）的能量

研究了加入敏化离子Ｃｒ３＋和Ｅｒ３＋的Ｔｍ：ＹＡＧ晶体的吸收谱和荧光谱，计算了Ｃｒ３＋、Ｅｒ３＋、Ｔｍ３＋离子的２Ｅ、４Ｉ１３／２、３Ｆ４能态的平均寿命及能量；转移效率、转移速率．得出Ｃｒ３＋→Ｔｍ３＋转移效率为８０％，转移速率为２．１×１０３ｓ－１．由（Ｅｒ，Ｔｍ）：ＹＡＧ的荧光谱可见存在Ｅｒ３＋→Ｔｍ３＋的有效的能量转移．讨论了Ｃｒ３＋→Ｔｍ３＋和Ｅｒ３＋→Ｔｍ３＋能量转移的不同．     

Enhancement of upconversion luminescence of YAlO3:Er3+ by Gd3+ doping

The upconversion luminescences of YAlO3:Er3+ phosphor co-doping with different Gd3+ concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO3 under 532-nm excitation. Moreover, the inactive Gd3+ ions can improve the upconversion intensity efficiently in a certain range of concentration. Under 980-nm excitation, the visible upconversion emissions at 546 and 646 nm are enhanced by about 10 and 8 times at the Gd3+ concentration of 40%, respectively. The upconversion emission at 410 nm under 532-nm excitation is also enhanced by 7 times. The substitution of Gd3+ ions for Y3+ sites changes the local symmetry of Er3+, leading to the improvement of upconversion efficiency.     

Dy3+单掺和Er3+,Yb3+共掺氧氟微晶玻璃的发光性能

采用高温熔融法和热处理工艺制作了含有GdF3纳米晶的氧氟微晶玻璃。在386 nm激发下,Dy3+掺杂氧氟微晶玻璃的发光强度明显增强,且蓝光对黄光的发光强度比逐渐增大,表明Dy3+已进入到GdF3纳米晶中。在980 nm激光器泵浦下,Er3+,Yb3+共掺氧氟微晶玻璃的上转换发光随着热处理温度的升高明显增强,Er3+的上转换发光出现明显的Stark分裂现象,这亦说明Er3+已进入到GdF3纳米晶相中。通过研究上转换发光强度与泵浦功率的关系,确定绿光上转换发光为双光子过程。     

High index of refraction via quantum interference in a three-level system of Er^3＋-doped yttrium aluminium garnet crystal

A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3＋ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.     

高浓度Er~(3+)掺杂Y_3Sc_2Ga_3O_(12)晶体的吸收光谱与晶体场模型研究

采用提拉法生长出了高浓度掺铒(35 at%)钇钪镓石榴石(Er:YSGG)激光晶体.测试了该晶体在340—1700 nm波段内的吸收光谱,对其中Er3+的实验能级进行了分析指认.用Er:YSGG的102个实验Stark能级,拟合了它的自由离子参数和晶体场参数,均方根误差(拟合精度)σ为10.34 cm-1.结果表明,参数化Stark能级的拟合结果与实验光谱符合得较好.将拟合得到的Er:YSGG实验结果与文献中已报道Er:YAG的自由离子参数和晶体场参数进行了比较.指出Er:YSGG具有较强的晶体场相互作用或许是其激光效率较高的主要原因之一.     

980 nm LD泵浦Er3+/Yb3+共掺Y2O3纳米粉所致热效应的研究

利用溶胶—凝胶方法制备了Er3+和Yb3+共掺杂的Y₂O₃纳米荧光粉。采用Er3+的2H_11/2→4I_15/2和4S_3/2→4I_15/2绿色上转换荧光强度比的方法,研究了由980 nm二极管激光器泵浦所导致的荧光粉样品表面温升现象。结果表明,随着泵浦功率的增加,样品表面温度大幅度上升, 当功率达到1 000 mW时,样品表面的温度达到820 K。该现象对分析稀土离子上转换过程中所出现的功率饱和现象起着重要的作用,并且在高温传感材料、医学生物细胞烧孔方面有着广阔应用前景。     

Er3+/Ce3+共掺TeO2-Bi2O3-TiO2玻璃的热稳定性和光谱特性研究

用高温熔融法制备了Er³⁺/Ce³⁺共掺新型碲酸盐玻璃(TeO₂-Bi₂O₃-TiO₂).采用差热分析方法研究了玻璃的热稳定性,测试并分析了不同Ce³⁺离子掺杂浓度下Er³⁺离子的吸收光谱、上转换光谱和荧光光谱特性.研究结果表明,制备的碲酸盐玻璃具有很好的热稳定性,玻璃析晶温度Tx与玻璃转变温度Tg之差(ΔT=Tx-Tg)达到了185 ℃,高于其它文献的报道|同时,Ce3+离子共掺引入的能量转移(Ce³⁺∶2F5/2+Er³⁺∶4I11/2→Ce³⁺∶2F7/2+Er³⁺∶4I13/2)有效地抑制了Er³⁺离子上转换发光并显著增强了1.53 μm波段荧光强度,而发射截面随着Ce³⁺离子掺杂浓度相应增大.优异的热稳定性以及光谱性能揭示Er³⁺/Ce³⁺共掺碲酸盐玻璃是一种潜在的制备宽带掺铒光纤放大器的理想增益介质.     

纳米相氟氧化物玻璃陶瓷中Er3+Yb3+离子对的量子剪裁发光造成的强的光谱调制

研究了纳米相氟氧化物玻璃陶瓷中Er3+Yb3+离子对的量子剪裁发光造成的强的光谱调制现象。测量了Er3+Yb3+双掺纳米相氟氧化物玻璃陶瓷的X射线衍射谱、表面形貌、激发光谱、吸收光谱、和发光光谱;而且也与Tb3+Yb3+双掺纳米相氟氧化物玻璃陶瓷的相对应的光谱参数进行了比较。发现378 nm光激发样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV所导致的652.0 nm红色发光强度为522 nm光激发时的680.85倍和303.80倍;我们还发现378 nm光激发所导致的样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的 652.0 nm红色发光强度为样品(C) Er(0.5%)∶FOV 的491.05和184.12倍。我们还发现在378 nm光激发时的样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的{978.0和1 012.0 nm}红外发光强度依次分别为样品(C) Er(0.5%)∶FOV 的{58.00和293.62}倍和{25.11和 67.50}倍。更进一步,对于652.0 nm波长发光的激发谱,发现(A) Er(1%)Yb(8.0%)∶FOV和(B) Er(0.5%)Yb(3.0%)∶FOV的378.5 nm激发谱峰强度是(C) Er(0.5%)∶FOV的大约606.02和199.83倍。同时,也发现样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的一级量子剪裁红外1 012或978 nm发光强度为样品(D) Tb(0.7%)Yb(5.0%)∶FOV的二级量子剪裁红外976 nm发光强度的101.38和29.19倍。发现的该量子剪裁是目前所报道的最强的量子剪裁。因此,相信所发现的氟氧化物纳米玻璃陶瓷中Er3+Yb3+离子对的一级量子剪裁发光是强的可以作为量子剪裁层应用到提高晶硅太阳能电池的发电效率。研究结果也能加速对目前国际热点的下一代环保的光谱调制太阳能电池的探索。     

Er~(3+)及Er~(3+)/Yb~(3+)掺杂纳米晶CaWO_4的发光性质

利用共沉淀法制备了Er3+掺杂及Er3+/Yb3+共掺杂纳米晶CaWO4发光粉体,室温下观察到Er3+的下转换和上转换特征发射。研究了不同煅烧温度、不同掺杂浓度对Er3+离子特征发射的影响。结果表明:随着煅烧温度的升高,发射强度增强;掺杂浓度的改变,导致了Er3+的浓度猝灭现象,其适宜的掺杂原子数分数为0.6%。同时观测到O-W的电荷迁移态与稀土离子之间的能量传递现象,并给出了能量传递的模型。对Er3+的上转换研究观察到:在976nm激光激发下Yb3+对Er3+的上转换发射起到了很好的敏化作用,两个Yb3+同时将能量以共振方式传递给一个Er3+离子,Er3+、Yb3+共掺杂样品的绿光上转换过程展示了双光子过程。     

Up-conversion photoluminescence characteristics of Yb3+:Er3+:Tm3+ co-doped borosilicate glasses

Yb3+:Er3+:Tm3+ co-doped borosilicate glasses are prepared.Their strong up-conversion photoluminescence spectra in a range from ultra-violet to near-infrared,which are excited by a 978-nm laser diode,are measured,and the mechanisms of energy transfer among Yb3+,Er3+ and Tm3+ ions are discussed.The results show that there is an unexpected wavelength at 900-nm emission from Yb3+ Stark splitting levels to pump Tm3+ ions and there exists an optimum pump power.The concentration of the Tm3+ dopant gives rise to a prominent effect on the intensity of visible and near-infrared emissions for the Yb3+:Er3+:Tm3+ co-doped borosilicate glasses.     

An EPR study of Er3+ impurities in RbTiOPO4 single crystals

An electron paramagnetic resonance (EPR) study of Er³⁺ ions in single crystals of RbTiOPO₄ (RTP) is presented. The EPR spectra show the existence of six different Er³⁺ centres. The g-matrix has been determined for these centres from the analysis of the angular dependences of the spectrum in three planes of the crystal. The study supports that erbium can enter the Rb⁺ and Ti⁴⁺ low-symmetry sites of RTP. This conclusion differs from those for KTP:Er³⁺ and RTP codoped with Nb and Er. The different occupancies found for Er in these various crystals is suggested to be due to the differences in Er concentration.     

掺Er3+/Yb3+氟氧玻璃的上转换发光特性

制备了新的Er³⁺/Yb³⁺共掺氟氧硅酸盐微晶玻璃,测试了材料的荧光光谱和吸收光谱。上转换光谱表明:有红(645 nm)、绿(545,522 nm)、蓝(480 nm)4个发光中心,分别对应Er³⁺的⁴F_9/2→⁴I_15/2、⁴S_3/2→⁴I_15/2、²H_11/2→⁴I_15/2、⁴F_7/2→⁴I_15/2 跃迁。发光曲线拟合斜率分别为1.81、2.39、1.95、2.15,均为双光子吸收过程。样品经热处理降低了声子能量,大大提高了上转换效率。采用Judd-Ofelt理论对样品光谱进行了分析,拟合得到了强度参数。