SPECTRA,ENERGY LEVELS AND UP-CONVERSION EFFECT OF ERBIUM IONS IN LiNbO3 CRYSTALS

The Optical properties and spectral data of erbium-doped Lithium Niobate crystals,including absorption spectrum, emission spectrum, luminescence lifetime and up-conversion effects are reported in this paper. The energy level scheme, Stark splitting under crystal field and up-conversion mechanism are discussed in detail. The possible applications of this material in waveguide optics and opto-electronics are also prospected.     

Er:ZBLAN玻璃的一光束上转换立体显示的初步研究

本文研究了一光束上转换三维立体显示 ,所用材料为Er:ZBLAN氟化物玻璃 ;利用 96 6nm的连续波半导体激光研究了一光束上转换三维立体显示的尺寸效应 ,且得到了它的上转换发光谱 ;尤其是发现了基于 15 2 0nm的半导体激光激发的多光子上转换一光束三维立体显示的性能有大幅度提高 ,这在国际上还未见报道。     

SrAl2O4:Eu2+,Dy3+的上转换发光特性

铕镝共掺的铝酸锶是一种新型的绿色长余辉荧光材料 ,经可见 -紫外光激发后 ,能发出超长时间的余辉。本文首次用 980nm的红外激发光源激发SrAl2 O4 :Eu2 ,Dy3 磷光体后 ,在室温下观测到了SrAl2 O4 :Eu2 ,Dy3 的绿色上转换荧光。并测得了其上转换荧光光谱图。与其正常的荧光光谱图相比 ,两者的峰形及波峰的位置有很大的差异 ,这预示着两者有不同的发光机理 ,并就其发光机理进行了初步的探讨。所用的样品经高温固相法合成后 ,用XRD表征。两种荧光光谱用荧光光谱仪测定。     

Single photon level spectrum measurement at fiber communication band using frequency up-conversion technology

We have developed a polarization independent (PI) spectrometer based on frequency up-conversion technology for single photon level spectrum measurement at the fiber communication band. To overcome the polarization dependence of the frequency up-conversion process, we use two periodically poled lithium niobate (PPLN) waveguides with a polarizing beam splitter. We experimentally study the sensitivity and resolution of the PI up-conversion spectrometer. We demonstrate the spectrometer by way of a spectrum measurement of a single photon level signal in the communication band.     

Tm3+和Er3+共掺杂氟氧化物玻璃陶瓷材料结构和上转换发光性质的研究

报道了一种新的上转换氟氧化物玻璃陶瓷材料,组份为65GeO2-25NaF-10BaF2(MFG)。研究了Tm^3 和Er^3 共掺MFG玻璃陶瓷中的发光性质。通过X射线衍射和Raman散射分析了MFG玻璃陶瓷的结构性质。分别测量了Tm^3 和Er^3 共掺MFG玻璃及玻璃陶瓷和Er^3 单掺MFG玻璃中的红外发射谱（λex=488nm)和上转换发射谱（λex=978nm)。给出了稀土离子掺入微晶的证据;（1）和MFG：1mol%Tm^3 、2mol%Er^3 玻璃相比,在978nmLD激发下,MFG：1mol%Tm^3 、2mol%Er^3玻璃陶瓷中红色上转换发光大大增强,红不与绿光的比值大大提高。（2）在488nm激光激发下,玻璃陶瓷样品中Tm^3 离子1．7μm左右的发射光谱明显窄化。最后讨论了玻璃陶瓷这种结构上转换发光的影响和其在上转换发光及光通信中的应用潜力。     

Up-conversion luminescence phenomenon of Er~(3 ) ions in ErP_5O_(14) noncrystal glass

The up-conversion luminescence phenomenon was observed in ErP_5O_(14) noncrys-tal glass induced by pulsed DCM dye laser.Based on the difference between up-conversion ex-citation spectrum and absorption of ~4F_(9/2) and dependence of up-conversion fluorescence inten-sity on the exciting wavelength,it is found that the mechanism of up-conversion from ~4F_(9/2)level of ErP_5O_(14) noncrystal glass can not be ascribed to energy transfering between Er~(3 ) ions,a seguential absorption of two photons by a single ion should be responsible for these process.     

Up-conversion luminescence tuning in Er~(3+) -doped ceramic glass by femtosecond laser pulse at different laser powers

The up-conversion luminescence tuning of rare-earth ions is an important research topic for understanding luminescence mechanisms and promoting related applications. In this paper, we experimentally study the up-conversion luminescence tuning of Er~(3+)-doped ceramic glass excited by the unshaped, V-shaped and cosine-shaped femtosecond laser field with different laser powers. The results show that green and red up-conversion luminescence can be effectively tuned by varying the power or spectral phase of the femtosecond laser field. We further analyze the up-conversion luminescence tuning mechanism by considering different excitation processes, including single-photon absorption(SPA), two-photon absorption(TPA), excited state absorption(ESA), and energy transfer up-conversion(ETU). The relative weight of TPA in the whole excitation process can increase with the increase of the laser power, thereby enhancing the intensity ratio between green and red luminescence(I_(547)/I_(656)). However, the second ETU(ETU2) process can generate red luminescence and reduce the green and red luminescence intensity ratio I_(547)/I_(656), while the third ESA(ESA3) process can produce green luminescence and enhance its control efficiency. Moreover, the up-conversion luminescence tuning mechanism is further validated by observing the up-conversion luminescence intensity, depending on the laser power and the down-conversion luminescence spectrum under the excitation of 400-nm femtosecond laser pulse. These studies can present a clear physical picture that enables us to understand the up-conversion luminescence tuning mechanism in rare-earth ions, and can also provide an opportunity to tune up-conversion luminescence to promote its related applications.     

Er3+掺杂的锗铋酸玻璃光谱性质的研究

制备了一种新型掺Er3 锗铋酸盐玻璃。分析了吸收光谱和上转换荧光光谱,并应用Judd-Ofelt理论计算了锗铋酸盐玻璃的3个强度参量tΩ(t=2,4,6),分别为Ω2=3.35×10-20cm2,Ω4=1.34×10-20cm2以及Ω6=0.67×10-20cm2。研究了在两种不同的激发光下(980和808 nm)锗铋酸盐玻璃的发光机制。根据McCumber理论,分析了在1.55μm光通讯窗口的光谱性质,计算了能级4I13/2→4I15/2跃迁的受激发射截面,结果显示掺Er3 锗铋酸盐玻璃具有较宽的荧光半高宽和较大的受激发射截面。因此有希望成为高效的上转换发光材料和1.55μm光通讯材料。     

Intense upconversion luminescence in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass

Structural and up-conversion fluorescence properties in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass have been studied. The structure of novel bismuth-germanium glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wave numbers. The Raman spectrum investigation indicates that PbCl₂ plays an important role in the formation of glass network, and has an important influence on the up-conversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions ¹G₄→³H₆ and ¹G₄→³H₄, respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. This novel oxychloride bismuth-germanium glass with low maximum phonon energy (∼730 cm⁻¹) can be used as potential host material for up-conversion lasers.     

太赫兹目标RCS缩比测量技术

论述了国外基于微波上倍频、激光下变频、THz时域光谱三种典型太赫兹波目标雷达散射截面(RCS)缩比测试系统的构成、技术特点和应用范围。采用固态器件、基于微波上倍频技术集成研制了宽带太赫兹低频端目标RCS测量系统,采用基于扫频的时域法RCS测量技术和小角度旋转目标雷达合成孔径（ISAR）成像方法对小目标进行了电磁散射特性测量,获取了目标RCS和二维散射成像信息。     

YNbO_4粉末材料中Er~(3+)发光研究及其光谱性质J-O计算

为了研究Er~(3+)/Yb~(3+)共掺杂YNb O4粉末材料上转换发光特性,采用J-O理论计算了该材料的光谱性质。根据吸收谱各吸收峰面积拟合出谱线强度参数,并根据谱线强度参数计算出理论振子强度和实验振子强度,得到两者均方差为δrms=3.916×10-7。计算了YNb O4粉末材料中Er~(3+)粒子的跃迁几率、跃迁分支比及能级寿命等参数,并计算得到了Er~(3+)离子从能级2H11/2、4S3/2和4F9/2到基态辐射跃迁的受激发射截面。研究结果表明YNb O4材料是一种优良的上转换基质材料。     

电子陷获型红外上转换材料的光谱测试

本文通过对电子陷获型红外上转换材料的激发光谱和发光光谱特性曲线的测试,论证该材料与一般红外器件相比,具有响应光谱范围广(0.8～1.6μm)等优点,为该材料的推广应用提供了可靠的依据。     

Single photon frequency up-conversion and its applications

Optical frequency up-conversion is a technique, based on sum frequency generation in a non-linear optical medium, in which signal light from one frequency (wavelength) is converted to another frequency. By using this technique, near infrared light can be converted to light in the visible or near visible range and therefore detected by commercially available visible detectors with high efficiency and low noise. The National Institute of Standards and Technology (NIST) has adapted the frequency up-conversion technique to develop highly efficient and sensitive single photon detectors and a spectrometer for use at telecommunication wavelengths. The NIST team used these single photon up-conversion detectors and spectrometer in a variety of pioneering research projects including the implementation of a quantum key distribution system; the demonstration of a detector with a temporal resolution beyond the jitter limitation of commercial single photon detectors; the characterization of an entangled photon pair source, including a direct spectrum measurement for photons generated in spontaneous parametric down-conversion; the characterization of single photons from quantum dots including the measurement of carrier lifetime with escalated high accuracy and the demonstration of the converted quantum dot photons preserving their non-classical features; the observation of 2nd, 3rd and 4th order temporal correlations of near infrared single photons from coherent and pseudo-thermal sources following frequency up-conversion; a study on the time-resolving measurement capability of the detectors using a short pulse pump and; evaluating the modulation of a single photon wave packet for better interfacing of independent sources. In this article, we will present an overview of the frequency up-conversion technique, introduce its applications in quantum information systems and discuss its unique features and prospects for the future.     

铁电超微粒/硬脂酸LB膜的制备和光谱特性研究

用LB膜技术组装铁电超微粒，实验结果显示：LB膜中的铁电超微粒比较稳定，覆盖度也比较高，并且存在介电限域效应，在室温下具有光致发光现象；荧光光谱具有宽的发光带，激发光谱存在上转换现象. 关键词：     

掺Er~(3+)的氟氧化物微晶玻璃上转换及近红外光谱性质

研究了组份为46SiO2-46PbF2-5Al2O3-3ZnF2(mol%),外掺4ErF3(mol%)的氟氧化物玻璃样品在微晶化前后的性能。根据样品的DTA曲线分析了其热稳定性,测试了微晶化前后Er3+的吸收光谱、上转换及近红外荧光光谱,根据样品的XRD图谱对比得到了其微晶相PbF2。结合能级图和荧光光谱分析了微晶化对光谱性质的影响。研究表明,微晶化后上转换荧光强度得到了极大的提高,特别对667nm的红光,其作用更为明显,微晶化对1.5μm荧光的有效半高宽几乎没有影响,但却极大地削减了峰值发射截面,显著地减小了Δλeff×eδ。     

Yb3+,Er3+双掺上转换玻璃陶瓷

制备了以PbF₂+GeO₂+WO₃SiO₂+NaF为基质组分的Yb³⁺,Er³⁺双掺稀土离子上转换发光玻璃陶瓷。采用日本产Hitachi F-4500荧光光度计,激发波长为980nm,观测到样品在550nm处出现较强的上转换发光峰,在528nm处有一个次发光峰,在650nm处有一个相对较弱的发光峰,讨论了发射光谱的特征,建立上转换发光机制,并讨论了上转换发光特征,以及基质成分、制备工艺参数、稀土离子浓度对发光性能的影响。实验中发现c(Yb³⁺):c(Er³⁺)为5:1时,上转换玻璃陶瓷的熔融温度为950℃、退火温度为380℃时,其上转换发光效率最高。     

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。     

Er3+掺杂NaAl(MoO4)2的荧光光谱与上转换发光研究

用液相沉淀法制备得到掺稀土离子Er3+和Ce3+的NaAl( MoO4)2,X射线衍射图样显示NaAl(MoO4)2是单斜晶体结构.掺稀土离子Er3+和Ce3+的NaAl(MoO4)2的拉曼光谱研究表明,掺Er3+离子的NaAl(MoO,)2比掺Ce3+离子具有更强荧光性能,掺杂Er3+离子的NaAl( MoO4)2晶...     

Comprehensive research about the cooperative up-conversion luminescence of the ytterbium-doped oxyfluoride vitroceramics

The cooperative up-conversion blue luminescence of Yb^{3+} ion-doped oxyfluoride vitroceramic material (Yb:FOV) and the influence of co-doped Ho^{3+} ion, when excited by a 960 nm diode-laser, are studied in this paper. A strong blue 479.1 nm up-conversion luminescence of the Yb:FOV material is discovered. It is found that the 479.1 nm luminescence results from the cooperative up-conversion of the coupled states of the Yb^{3+}－Yb^{3+} clusters formed by two adjacent Yb^{3+} ions. The measured cooperative up-conversion luminescence main peak 479.1 nm of this paper is different from the characteristic fluorescence main peak of the Tb^{3+} ion positioned at about 495－504 nm wave-range. Our result coincides with all the published correct papers, whose cooperative up-conversion luminescence main peaks of the direct Yb^{3+}－Yb^{3+} clusters are all positioned at about 476－480 nm wave-range. All of these indicate that the large cooperative up-conversion blue luminescence of the direct Yb^{3+}－Yb^{3+} clusters discovered in this paper is stable. It further proves that the cooperative up-conversion green luminescence may result from the Yb^{3+}-Tb^{3+} cooperative effect. In particular, the original work of this paper improves considerably on the traditional concept by the experimental facts that the blue 479.1 nm cooperative up-conversion luminescence strength of Yb(5):FOV is 230 times greater than that of fluoride glass Yb(3):ZBLAN. This is a great development to meet the practical requirements for blue up-conversion luminescence strength. This result indicates that the large cooperative up-conversion blue luminescence could be achieved excellently by using a suitable material, such as oxyfluoride vitroceramic, which provides a better chance to form better Yb^{3+}－Yb^{3+} clusters and has less relaxation to keep the more efficient up-conversion luminescence. It is also found that impurities seriously reduce the cooperative up-conversion luminescence intensity due to the cross-relaxation from the Yb^{3+}－Yb^{3+} clusters, which means that the cooperative up-conversion blue luminescence could be further improved by pure Yb^{3+} ion-doped materials that have as few impurities as possible to reduce the cross-relaxation. The large cooperative up-conversion blue luminescence of Yb(5):FOV also comes from its higher concentration (5 mol%) of activator Yb^{3+} ion which acts well because the cooperative up-conversion blue luminescence intensity varies linearly against the square of the concentration of Yb^{3+} ions in the range of 0.5－5 mol%. In summary, the great improvement of our work on cooperative up-conversion blue luminescence results from the comprehensive enhancement of the factors of better-coupled chance of the Yb^{3+}－Yb^{3+} clusters, less cross-relaxation, better concentration contribution of Yb^{3+} activator, non-saturation, and better up-conversion luminescence efficiency.     

试验优化设计Tm3+/Yb3+共掺钼酸钇钠荧光粉上转换发光性质的研究

为得到最大发光强度的Tm³⁺/Yb³⁺共掺钼酸钇钠荧光粉, 采用试验优化设计的方法建立发光强度与Tm³⁺/Yb³⁺掺杂浓度的回归方程, 再通过遗传算法优化算出方程的最大解. 利用高温固相法制备出了该解的Tm³⁺/Yb³⁺共掺钼酸钇钠荧光粉样品. 在980 nm抽运激发下, 测量了样品的上转换荧光发射谱, 分析了上转换发光机制, 在室温下观察到强烈的蓝光(476 nm)和微弱的红光(649 nm)发射, 其分别对应于Tm³⁺的¹G₄→³H₆ 和¹G₄ →³F₄ 跃迁. 在Tm³⁺/Yb³⁺ 上转换发光体系中, ¹G₄ 的上转换可见发射是双光子合作上转换能量传递过程. 并探讨了样品的温度效应, 发现该样品蓝光发光强度随温度升高而减弱, 并对其温度猝灭机理进行了解释. 关键词： 试验优化设计 上转换 钼酸钇钠 3+/Yb³⁺')" href="#">Tm³⁺/Yb³⁺