871 resultados para (n < 1.54)


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近年来,随着激光告警、激光指示、风速测量、激光雷达尤其是激光美容等方面的需求逐渐增加,要求掺铒激光玻璃能够实现比以往更高重复频率以及更大能量的激光输出,其中对脉冲能量的要求达1~10 J。

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α-(Yb1-xErx)2Si2O7 thin films on Si substrates were synthesized by magnetron co-sputtering. The optical emission from Er3+ ions has been extensively investigated, evidencing the very efficient role of Yb-Er coupling. The energy-transfer coefficient was evaluated for an extended range of Er content (between 0.2 and 16.5 at.%) reaching a maximum value of 2 × 10⁻¹⁶ cm⁻³s⁻¹. The highest photoluminescence emission at 1535 nm is obtained as a result of the best compromise between the number of Yb donors (16.4 at.%) and Er acceptors (1.6 at.%), for which a high population of the first excited state is reached. These results are very promising for the realization of 1.54 μm optical amplifiers on a Si platform.

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Er/Bi codoped SiO2 thin films were prepared by sol-gel method and spin-on technology with subsequent annealing process. The bismuth silicate crystal phase appeared at low annealing temperature while vanished as annealing temperature exceeded 1000 degrees C, characterized by X-ray diffraction, and Rutherford backscattering measurements well explained the structure change of the films, which was due to the decrease of bismuth concentration. Fine structures of the Er3+-related 1.54 mu m light emission (line width less than 7 nm) at room temperature was observed by photoluminescence (PL) measurement. The PL intensity at 1.54 gm reached maximum at 800 degrees C and decreased dramatically at 1000 degrees C. The PL dependent annealing temperature was studied and suggested a clear link with bismuth silicate phase. Excitation spectrum measurements further reveal the role of Bi3+ ions for Er3+ ions near infrared light emission. Through sol-gel method and thermal treatment, Bi3+ ions can provide a perfect environment for Er3+ ion light emission by forming Er-Bi-Si-O complex. Furthermore, energy transfer from Bi3+ ions to Er3+ ions is evidenced and found to be a more efficient way for Er3+ ions near infrared emission. This makes the Bi3+ ions doped material a promising application for future erbium-doped waveguide amplifier and infrared LED

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采用等离子体增强化学汽相沉积技术生长不同氧含量的氢化非晶氧化硅薄膜(a-SiO_x:H),离子注入铒及退火后在室温观察到很强的光致发光。当材料中氧硅含量比约为1和1.76时,分别对应77K和室温测量时最强的1.54μm光致发光。从15到250K的变温实验显示出三个不同的强度与温度变化关系,表明氢化非晶氧化硅中铒离子的能量激发和发光是一个复杂的过程。提出氢化非晶氧化硅薄膜中发生铒离子来自于富氧区,并对实验现象进行了解释。氢化非晶氧化硅中铒发光的温度淬灭效应很弱。从15到250K,光致发光强度减弱约1/2。

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利用等离子体增强化学气相淀积(PECVD)技术生长氧、硼、磷掺杂的氢化非晶硅薄膜。在室温下注入铒离子后研究三种掺杂元素对铒离子发光的作用。室温下观察到很强的光致发光现象。氧的引入并且和铒离子形成发光中心,提高了铒离子的发光强度。退火实验表明氧、硼、磷的掺杂补偿了材料中的缺陷,提高了氢的逃逸温度,改善材料的热稳定性,使材料的退火温度因掺杂元素的加入而提高,铒的发光得到增强。讨论了铒离子的发光机制。

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材料科学开放实验室基金,光学信息技术科学教育部开放实验室基金

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国家自然科学基金,国家攀登计划

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在a-Si:H和a-SiCx:H中共注稀土铒和氧。300 ℃和400 ℃热退火后,测得了来自发光中心Er~(3+)内层4f电子跃迁的1.54 μm光致发光。400 ℃是较好的退火温度。随着碳含量的增加,发光强度逐渐减弱,这可能是由于碳的引入减弱了间隙氧退火时的迁移能力所致。

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分别在InP、GaAs和Si中以7×10<′14>和1×10<′15>cm<′-2>的剂量进行Er离子注入, 并采用闭管、快速和炉退火等热处理。低温光致发光(PL)、反射式高等电子衍射和卢瑟福背散射实验研究表明, 上述样品中Er<′3+>离子特征发光的中心波长均出现在1.5μm处, 其中InP的发光峰最强, 而注入损伤的恢复是影响Er<′3+>发光的重要因素之一。卢瑟福背散射分析进一步证实退火后Er原子在Si中向表面迁移, 而在InP中的外扩散较小, 并比较了Er在InP和Si晶格中的占位情况。图7参12

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The crystal structure of Er(PM)(3)(TP)(2) [PM = 1-Phenyl-3-methyl-4-isobutyryl-5-pyrazoloiie, TP = triphenyl phosphine oxide] was reported and its photoluminescence properties were studied by UV-vis absorption, excited, and emission spectra. The Judd-ofelt theory was introduced to calculate the radiative transition rate and the radiative decay time of 3.65 ms for the I-4(13/2) -> I-4(15/2) transition of Er3+ ion in this complex.

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Infrared emission at 1.54 mu m excited optically and electrically from an erbium organic compound tris(acetylacetonato)(1,10-phenanthroline) erbium [Er(acac)(3)(phen)] is observed. The rare-earth complex is dispersed into a polymer matrix of poly(N-vinylcarbazole) (PVK) to fabricate an electroluminescent (EL) device with an ITO/PVK:Er(acac)(3)(phen)/Al:Li/Ag structure, where ITO represents indium-tin-oxide-coated glass. The device shows infrared EL emission at 1.54 mu m, which suggests a simple and cheap method to obtain a light source for 1.54-mu m-wavelength devices in optical communications. (C) 2000 American Institute of Physics. [S0021-8979(00)00301-7].