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61.
Kaushik Biswas Sathravada Balaji Debarati Ghosh Annapurna Kalyandurg 《International Journal of Applied Glass Science》2017,8(2):204-215
In this work, effect of glass composition as well as ceramization on visible and near-infrared (NIR) luminescence properties along with their decay dynamics of Er3+ ions has been compared considering two different oxyfluoride glasses yielding BaF2 and BaGdF5 nanocrystals. Both the glass systems have exhibited an intense normal and upconversion green emission under ultraviolet (378 nm) and NIR (978 nm) excitations, respectively. A remarkable enhancement of these emission intensities is observed for gadolinium-(Gd) containing glasses. Interestingly, NIR fluorescence intensity from Er3+ ions at 1540 nm has showed marginal decrease in gadolinium-containing glass which is attributed to occurrence of strong excited-state absorption (ESA) due to higher fluorine content ensuing an augmentation of upconversion green emission with a concomitant decrease in NIR emission. The quadratic dependence of upconversion green emission intensity on its pump power for all the samples revealed biphotonic absorption process from ground-state 4I15/2 to the excited-state 4I11/2 followed by ESA of second photon to the 4F7/2 level. The intense green upconversion emission as well as enhanced NIR fluorescence lifetimes indicate the suitability of these glass/glass ceramics for upconversion lasers and amplification in the third telecom window. 相似文献
62.
Philipp Sippel Simon Heitz Mikaela Elagin MykhayloP. Semtsiv Rainer Eichberger W. Ted Masselink Thomas Hannappel Klaus Schwarzburg 《Progress in Photovoltaics: Research and Applications》2016,24(3):307-314
We have realized a tandem solar cell design that combines a pin‐junction with a photovoltaic intersubband absorber. This concept allows harvesting light in the visible range and the near‐ and mid‐infrared at the same time, and theoretically, energy conversion efficiencies beyond the Shockley–Queisser‐limit could be achieved. A test structure was grown, and the operation of this concept could be confirmed, in principal with an optical two‐beam experiment. The basic characteristics of the device can be explained with an equivalent circuit design that consists of three individual cells, and we find an obvious analogy to the concept of the intermediate band solar cell with noteworthy advantages at some points. Our results show, that for a working device it is crucial to adjust the properties of the photovoltaic intersubband absorber for optimal charge separating performance at the working point of the solar cell. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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This study reported the frequency characteristics of series photodetector frequency circuit system for detection of fluorescence dye concentration. In the condition of the same fluorescence intensity, the series photodetector frequency circuit system with higher responsivity of photodetector had higher frequency shift. The 100 MHz series photodetector frequency circuit system was applied to determine the fluorescence dye concentration of HEX by frequency shift. The correlation curve showed that the frequency shift was linearly related to the logarithm of fluorescence dye concentration from 100 pmol 3 μl−1 to 10 amol 3 μl−1. The proposed method can be applied simply and the detection limit of fluorescence dye concentration was lower than the conventional fluorescence technique by 2–3 orders. 相似文献
66.
叶海水 《上海电力学院学报》2010,(12)
采用长焦距单透镜方案,研制了一种新型的高性能近红外平行光管。以单模光纤导出的近红外激光(λ=1053nm)为光源,设计了满足光强均匀性要求的准直物镜焦距,使用新型的近红外消光涂料消除了杂散光的影响,并运用双平板剪切干涉技术完成了平行光管的不可见光束调校。采用自制的1053nm近红外干涉系统测试了平行光管的光学质量,结果表明,准直后的出射光束波面峰谷值(PV)达到0.045λ,光强的均匀性达79.2%。 相似文献
67.
二维近红外光谱定量分析内燃机油粘度指数性能的研究 总被引:4,自引:0,他引:4
针对常规近红外光谱技术测试内燃机油性能指标的不足,提出了以电压为外扰方式,获取内燃机油二维近红外光谱的技术。对内燃机油样品进行二维相关光谱分析可以定性分析内燃机油粘度等级。使用来自不同厂家、不同质量等级的35个内燃机油样品建立多维偏最小二乘(N-PLS)模型对内燃机油粘度指数进行了预测研究。结果表明,内燃机油的二维近红外光谱中含有与粘度指数相关的信息,使用N-PLS模型能够实现对内燃机油粘度指数的定量分析。该方法的提出为研究复杂对象性能指标的快速检测提供了一种新的技术手段。 相似文献
68.
Kimberly Sablon Andrei Sergeev Nizami Vagidov Andrei Antipov John Little Vladimir Mitin 《Nanoscale research letters》2011,6(1):584
We analyze the effect of doping on photoelectron kinetics in quantum dot [QD] structures and find two strong effects of the built-in-dot charge. First, the built-in-dot charge enhances the infrared [IR] transitions in QD structures. This effect significantly increases electron coupling to IR radiation and improves harvesting of the IR power in QD solar cells. Second, the built-in charge creates potential barriers around dots, and these barriers strongly suppress capture processes for photocarriers of the same sign as the built-in-dot charge. The second effect exponentially increases the photoelectron lifetime in unipolar devices, such as IR photodetectors. In bipolar devices, such as solar cells, the solar radiation creates the built-in-dot charge that equates the electron and hole capture rates. By providing additional charge to QDs, the appropriate doping can significantly suppress the capture and recombination processes via QDs. These improvements of IR absorption and photocarrier kinetics radically increase the responsivity of IR photodetectors and photovoltaic efficiency of QD solar cells. 相似文献
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Yi-Ju Chen 《Microelectronics Journal》2006,37(9):985-992
This paper presents an integrated optical receiver that operates at 1 Gb/s in a standard 0.35 μm digital CMOS technology. The receiver consists of an integrated CMOS photodetector, a transimpedance amplifier (TIA) followed by a post-amplification stage and a dual-loop clock and data recovery (CDR) circuit. At a wavelength of 860 nm, the circuit requires an average light input power of −19.7 dBm to obtain a bit-error rate (BER) of 10−12. The complete receiver consumes a total power of approximately 155 mW from a 3.3-V supply. The core circuit area is 0.85×1.32 mm2. 相似文献