174 resultados para CROSS-SECTION DEPENDENCE
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this paper is retracted
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Yb-doped and Yb-Al-codoped high silica glasses have been prepared by sintering nanoporous glasses. The absorption, fluorescent spectra and fluorescent lifetimes have been measured and the emission cross-section and minimum pump intensities were calculated. Codoping aluminum ions enhanced the fluorescence intensity of Yb-doped high silica glass obviously. The emission cross-sections of Yb-doped and Yb-Al-codoped high silica glasses were 0.65 and 0.82 pm(2), respectively. The results show that Yb-Al-codoped high silica glass has better spectroscopic properties for a laser material. The study of high silica glass doped with ytterbium is helpful for its application in Yb laser systems, especially for high-power and high-repetition lasers. (C) 2007 Elsevier B.V. All rights reserved.
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Broadband infrared luminescence is observed in various Bi-doped oxide glasses prepared by conventional melting-quenching technique. The absorption spectrum of the Bi-doped germanium oxide glass consists of five broad peaks at below 370, 500, 700, 800 and 1000 nm. The fluorescence spectrum exhibits a broad peak at about 1300 nm with full width at half maximum (FWHM) of more than 300 nm when excited by an 808 nm laser diode. The fluorescence lifetime at room temperature decreases with increasing Bi2O3 concentration. Influence of the glass composition and melting atmosphere on the fluorescence lifetime and luminescent intensity is investigated. The mechanism of the broadband infrared luminescence is suggested. The product of stimulated emission cross-section and lifetime of the Bi-doped aluminophosphate glass is about 5.0 X 10(-24) cm(2) s. The glasses might be promising for applications in broadband optical fiber amplifiers and tunable lasers. (c) 2007 Elsevier B.V. All rights reserved.
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研究了碱金属和碱土金属离子修饰的掺Er^3+氟磷酸盐玻璃的光谱性质,讨论了碱金属和碱土金属对铒氟磷玻璃的吸收和发射截面、荧光半高宽,Judd-Ofelt强度参数和上转换发光强度等光谱性质的影响,并与一些传统氧化物玻璃系统进行了比较.研究表明碱金属K^+和碱土金属Sr^2+掺杂高的玻璃更适宜用作光放大器基质.含12mol%K^+的氟磷玻璃展现出7.83×10^-21cm^2的高发射截面和最小的荧光上转换强度;含23mol%Sr^2+的氟磷玻璃则有7.58×10^-21cm^2的高发射截面、65nm的荧光半高
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研究了Na2O含量对Na2O-Al2O3-SiO2(NAS)玻璃的光谱性质的影响。利用Judd-Ofelt(J-O)理论和吸收光谱计算了Er^3+掺杂的铝硅酸盐玻璃的Ωt参数、自发辐射几率和自发辐射寿命,分析了Ωt参数与Na2O含量的关系以及与吸收截面,Er^3+离子^4I13 2能级的自发辐射几率和荧光半峰全宽(FWHM)等性质的关系。随Na2O含量的增加.J-O参数Ωt(t=2,4,6)减小,Er^3+离子1533nm的吸收截面和荧光半峰全宽.Er^3+离子^4I13 2能级的自发辐射几率也减小,而E
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通过优化熔融条件和玻璃组份,成功开发出一种新的Er^3+/Yb^3+共掺磷酸盐玻璃,其在沸水和熔盐中均表现出很好的化学稳定性。通过分析室温下Er^3+/Yb^3+共掺磷酸盐玻璃的吸收光谱,计算得到了Er^3+离子在波长1533nm处的峰值发射截面和杜得-奥菲而特强度参数;其中Er^3+离子在波长1533nm处的峰值发射截面为0.72×10^20cm^2,大于Schott的IOG1玻璃中Er^3+离子的峰值发射截面0.67×10^-20cm^2。通过改变离子交换的条件,获得了1.55μm单模光波导的制作条件
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An efficient diode-pumped laser was demonstrated by using an ytterbium-doped laser crystal, Yb:Gd2SiO5 (Yb:GSO), wherein Yb3+ ions exhibit the largest ground-state splitting among all the ytterbium-doped crystals. The Yb:GSO laser can be operated at a low pumping threshold, and the most efficient laser occurs around 1088 nm since the corresponding emission band has the largest emission cross section and the lowest thermal population. A slope efficiency of 75% was demonstrated for a continuous-wave Yb:GSO laser at 1094 nm, and self-pulsed lasers were achieved within the tunable range of 1091-1105 nm, which are the longest laser wavelengths achieved for Yb3+ lasers. (c) 2006 American Institute of Physics.