共查询到18条相似文献,搜索用时 79 毫秒
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表面等离激元与量子发射体间的强耦合现象通常通过散射、吸收以及荧光等远场光谱探测方法进行研究.利用高度聚焦的电子束,电子能量损失谱能够实现亚纳米尺度的局域探测,可以更加有效地研究强耦合现象.本文在理论上分别模拟了银纳米棒、介质材料以及介质层包裹银纳米棒复合结构的电子能量损失谱.得到了可以与实验结果比拟的银纳米棒表面等离激元的电子能量损失谱.在上述复合结构的电子能量损失谱中观察到了谱峰的拉比劈裂,探究了银纳米棒尺寸对拉比劈裂的影响.分别在红外、可见光波段讨论了介质层的元激发与银纳米棒偶极辐射及高阶非辐射表面等离激元模式间的强耦合现象,从损失谱的空间分布成像角度探讨了强耦合引起的杂化等离激子(plexciton)的形成.本研究对强耦合现象的进一步实验和理论研究具有指导意义. 相似文献
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结合扫描隧道显微镜(STM)与电子能谱仪是实现表面微区元素分析的途径之一.我们将环形电子能量分析器和三维扫描探针系统相结合,建立了一台扫描探针电子能谱仪(SPEES).通过测量针尖近场发射束流激发的Au表面能量损失谱,我们用研究了Au原子的等离子体激元激发现象.进一步通过改变针尖-样品距离,我们研究了Au等离子体激元峰与弹性散射峰的强度比随针尖-样品距离变化的关系.研究结果发现该强度比与针尖-样品距离的关系并不是单调变化,而是在一个特定位置存在极大. 相似文献
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表面等离激元——机理、应用与展望 总被引:1,自引:0,他引:1
等离激元光子学(plasmonics)的研究内容是金属纳米结构独特的光学性质及其应用.随着纳米科技的进步,等离激元光子学已经迅速发展成为一门新兴学科,在生物、化学、能源、信息等领域具有重要的应用前景.文章主要介绍表面等离激元(surface plasmons,SPs)的一些基本物理性质,包括局域的表面等离激元(localized surface plas-mon,LSP)和传导的表面等离激元(propagating surface plasmon polariton,SPP),文章还介绍了表面等离激元的几个重要的应用方向,例如生物/化学传感器、表面等离激元激光、光开关器件以及表面等离激元光逻辑运算,等等. 相似文献
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金属纳米结构的表面等离激元可以突破光学衍射极限,为光子器件的微型化和集成光学芯片的实现奠定基础.基于表面等离激元的各种基本光学元件已经研制出来.然而,由于金属结构的固有欧姆损耗以及向衬底的辐射损耗等,表面等离激元的传输能量损耗较大,极大地制约了其在纳米光子器件和回路中的应用.研究能量损耗的影响因素以及如何有效降低能量损耗对未来光子器件的实际应用具有重要意义.本文从纳米线表面等离激元的基本模式出发,介绍了它在不同条件下的场分布和传输特性,在此基础上着重讨论纳米线表面等离激元传输损耗的影响因素和测量方法以及目前常用的降低传输损耗的思路.最后给出总结以及如何进一步降低能量损耗方法的展望.表面等离激元能量损耗的相关研究对于纳米光子器件的设计和集成光子回路的构建有着重要作用. 相似文献
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采用边界元方法研究了快电子在金属纳米双线中激发间隙表面等离激元(SPP)的性质,比较了在不同横截面形状(包括圆形、尖劈形和不规则形状)下电子所激发SPP的不同.研究表明:在以上波导结构中,快电子都能激发具有较长传播距离和较好局域性的低阶单级-单级耦合的间隙等离激元模式;同时通过对波导无量纲价值参数的比较,发现快电子在纳米双线中激发间隙等离激元对双线波导的横截面形状要求不高,横截面形状真正影响的是高阶等离激元模式的激发,而且快电子在截面形状为尖劈的双线波导中能激发局域性更强的间隙SPP.该研究将对实验中利用
关键词:
表面等离激元
间隙模式
金属纳米波导 相似文献
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The origin behind crystalline silicon surface passivation by Al2O3 films is studied in detail by means of spatially‐resolved electron energy loss spectroscopy. The bonding configurations of Al and O are studied in as‐deposited and annealed Al2O3 films grown on c‐Si substrates by plasma‐assisted and thermal atomic layer deposition. The results confirm the presence of an interfacial SiO2‐like film and demonstrate changes in the ratio between tetrahedrally and octahedrally coordinated Al in the films after annealing. These observations reveal the underlying origin of c‐Si surface passivation by Al2O3. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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We demonstrate that high-energy, high-resolution reflection electron energy loss spectroscopy can provide unique insights into interface formation, especially for the case where an extended interface is formed. By changing the geometry and/or electron energy the electronic structure can be probed over a range of thicknesses (from 10s of Å to more than 1000 Å). At the same time one resolves the elastically scattered electrons into different components, corresponding to scattering of atoms with different mass (so-called ‘electron Rutherford backscattering’). Thus these high-energy REELS/elastic scattering experiments obtain information on both the electronic structure and the atomic composition of the overlayer formed. 相似文献
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Chinthaka K. Wijesinghe M. Ikeda N. Nagashima 《Journal of Electron Spectroscopy and Related Phenomena》2003,130(1-3):57-64
The reactions of Si(100) and Si(111) surfaces at 700 °C (973 K) with ethylene (C2H4) at a pressure of 1.3×10−4 Pa for various periods of time were studied by using Auger electron spectroscopy (AES) and electron energy loss spectroscopy (ELS). For a C2H4 exposure level, the amount of C on the (111) surface was larger than that on the (100) surface. The formation of β-SiC grain was deduced by comparing the CKLL spectra from the sample subjected to various C2H4 exposure levels, and from β-SiC crystal. 相似文献
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Recent experimental findings concerning electron energy loss spectroscopy in -Perylene-tetracarboxylic-dianhydride are analysed in terms of a Frenkel exciton model. Taking into account the energy dispersion of excitations with finite momentum transfer, the k-dependence of the dielectric tensor and the corresponding electron energy loss functions can be calculated. The exciton dispersion with a minimum at k≠0 yields a red shift of the lineshape of loss functions at large k, as observed experimentally. 相似文献
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The influences on the neutrino energy loss rates in iron group nuclei
at the same density are investigated in the presence of strong
electron screening and in the absence of electron screening. The
results show that at a temperature of $15\ti10^9$\,K, the neutrino
energy loss rates which come from the electron capture process for
most iron group nuclei decrease no more than 2 orders of magnitude
but for the others (such as $^{53,55,56,57,58,59,60}$Co,
$^{56,59}$Ni) they can decrease about 3 orders of magnitude due to
strong electron screening (SES), whereas, at a temperature of $10^9K$
the neutrino energy loss rates of the most iron group nuclei can be
diminished greatly due to the SES. For example, $^{61}$Fe, $^{60}$Fe,
and $^{62}$Ni the neutrino energy loss rates decrease about 4, 15 and
16 orders of magnitude and for $^{57}$Cr, $^{58}$Cr, and $^{60}$Cr
decrease about 18, 12, and 10 orders of magnitude respectively.
According to our calculations the neutrino energy loss rates of
nuclei $^{58}$Mn, $^{59}$Mn, $^{60}$Mn, and $^{62}$Mn may decrease
about 13 orders of magnitude at a temperature of $10^9$\,K due to the
SES. 相似文献
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随着科学技术的不断发展,人们正在寻求更新的实用材料.金属氧化物,包括金属氧化物薄膜的各种实用材料,在工业界、信息产业界和能源开发等方面的应用前景,早已引起国内外学者的极大关注.例如,由于氧化物具有各种特殊的介电和光学性质,研究和开发基于氧化物薄膜的气敏材料非常热门.如何制备出有实用价值的各种薄膜材料,是科学家们一直关心和深入研究的课题.电子能谱技术在各种材料的基础研究和实际应用中起着重要的作用.本文以有序金属氧化物薄膜研制为例,简要评述了电子能谱技术(包括X射线光电子能谱(XPS),紫外光电子能谱(UPS),俄歇电子能谱(AES)和高分辨电子能量损失谱(HREELS)),以及低能电子衍射(LEED)等技术在氧化物薄膜材料制备和表征中的应用. 相似文献
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随着科学技术的不断发展,人们正在寻求更新的实用材料.金属氧化物,包括金属氧化物薄膜的各种实用材料,在工业界、信息产业界和能源开发等方面的应用前景,早已引起国内外学者的极大关注.例如,由于氧化物具有各种特殊的介电和光学性质,研究和开发基于氧化物薄膜的气敏材料非常热门.如何制备出有实用价值的各种薄膜材料,是科学家们一直关心和深入研究的课题.电子能谱技术在各种材料的基础研究和实际应用中起着重要的作用.本文以有序金属氧化物薄膜研制为例,简要评述了电子能谱技术(包括X射线光电子能谱(XPS),紫外光电子能谱(UPS),俄歇电子能谱(AES)和高分辨电子能量损失谱(HREELS)),以及低能电子衍射(LEED)等技术在氧化物薄膜材料制备和表征中的应用. 相似文献
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Experimental reflection electron energy loss (REEL) spectra are measured from aluminum for primary energies ranging from 130 eV to 2 keV. A Monte Carlo simulation is shortly described and used to calculate the same spectra. The focus is on reproducing the variable weight of surface and bulk losses as the surface sensitivity of spectra changes by changing the primary electron energy. The intensity of surface losses in the simulations is modulated by the thickness of the region where surface excitations occur. Simulations based either on a constant or an energy-dependent thickness for this layer are considered. In both cases, simulated spectra reproduce the experimental trend as a function of energy, though the correct surface-to-bulk intensity ratio for each energy is either underestimated or overestimated. 相似文献