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Quantitative analysis of the self-absorption and reemission effects on the emission spectrum of photoluminescence in right-angle excitation–detection configuration 下载免费PDF全文
A theoretical approach based on differential radiative transport is proposed to quantitatively analyze the selfabsorption and reemission effects on the emission spectrum for right angle excitation–detection photoluminescence measurements,and the wavelength dependence of the reemission effect is taken into account.Simulations and experiments are performed using rhodamine 6G solutions in ethanol as model samples.It is shown that the self-absorption effect is the dominant effect on the detected spectrum by inducing pseudo red-shift and reducing total intensity;whereas the reemission effect partly compensates for signal decrease and also results in an apparent signal gain at the wavelengths without absorption.Both effects decrease with the decrease in the sample concentration and the propagation distance of the emission light inside the sample.We therefore suggest that diluted solutions are required for accurate photoluminescence spectrum measurements and photoluminescence-based measurements. 相似文献
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系统介绍了几种基于瞬态光克尔效应的超快光学快门技术,包括传统的光克尔双折射快门技术,瞬态光栅快门技术,以及利用瞬态克尔透镜效应的光学快门技术。这些技术都是在泵浦-探测的实验配置基础上,利用门控光对克尔介质折射率的瞬态调制导致的信号光的相位(偏振态)、传播方向或光束发散角等光学特性的改变实现对信号光的超快时间分辨测量。对比讨论了这些超快快门技术的工作原理和实验配置,结果表明瞬态光束偏折快门技术相比其他快门技术具有无偏振配置要求、无相位匹配条件、超宽带光谱响应范围的特点,在光与物质相互作用的超快动力学研究中具有更为广阔的应用前景。 相似文献
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The properties of Raman phonons are very important due to the fact that they can availably reflect some important physical information. An abnormal Raman peak is observed at about 558 cm-1 in In film composed of In/InOx core-shell structured nanoparticles, and the phonon mode stays very stable when the temperature changes. Our results indicate that this Raman scattering is attributed to the existence of incomplete indium oxide in the oxide shell. 相似文献
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We investigate the MgO codoping-induced effect on the luminescent properties of Er^3 -doped and Er/Mg codoped LiNbO3 crystals. The emission and excitation spectra and the absorption spectra are measured. The results show that the luminescent behaviour of Er^3 ions is very sensitive to the codoping of Mg^2 ions. According to the photorefractive level theory, we propose a quench model for the Er/Mg codoped lithium niobate crystal. The quench centres are suggested to be the bipolaron (NbLi-NbNb), we attribute the luminescent enhancement to the decreasing concentration of these centres. The luminescent enhancement effect is successfully explained. 相似文献
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随着纳米科技和微纳电子器件的发展,制造业对微纳加工技术的要求越来越高.激光加工技术是一种绿色先进制造技术,具有巨大的发展潜力,己广泛应用于不同的制造领域.为实现低成本、高效率、大面积尤其是高精度的激光微纳加工制造,研究和发展激光超衍射加工技术具有十分重要的科学意义和应用价值.本文首先阐述了基于非线性效应的远场激光直写超衍射加工技术的原理与国内外发展状况,包括激光烧蚀加工技术、激光诱导改性加工技术和多光子光聚合加工技术等;然后介绍了几种基于倏逝波的近场激光超衍射加工技术,包括扫描近场光刻技术、表面等离子激元光刻技术等新型超衍射激光近场光刻技术的机理与研究进展;最后对激光超衍射加工中存在的问题及未来发展方向进行了讨论. 相似文献
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Normalized Mandel Parameter (Q) is introduced as a new measurement oi photon statistics. Dependences of Mandel parameter Q and corresponding normalized Mandel parameter (Q) on photon-counting time interval are experimentally investigated for pseudo-thermal light. We demonstrate that (Q) is more appropriate than Q, to measure the statistical deviation from Poisson distribution, because (Q) presents clearly both the intrinsic statistical properties and measuring effects. The advantages of (Q) in charactering nonclassical emissions are also discussed. 相似文献
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Preparation and Size Characterization of Silver Nanoparticles Produced by Femtosecond Laser Ablation in Water 下载免费PDF全文
Femtosecond laser ablation of silver plate placed in water is used to produce nanoparticle suspension. The method is easy to operate and the suspension is relatively stable. The optical properties and the size distribution of the suspension are studied with UV-vis absorption spectroscopy and dynamic light scattering, respectively. The shape of the nanoparticles is investigated by an atomic force microscope, which is near spherical. There are two kinds of nanoparticles, small particles with diameter about 35 nm, and large particles with diameter about 120 nm. 相似文献