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1.
Analysis of Second-Harmonic Generation from CuttbPc LB Film/Metal Interface 总被引:1,自引:0,他引:1
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Second-harmonic generation signals from a CuttbPc LB film deposited on metal (Al or Au)-glass substrates were investigated. It was observed that there were two second-harmonic peaks at the wavelength of 1060 and 1250nm in the CuttbPc/Al film, but only one peak at 1050nm in the CuttbPc/Au film. Meanwhile the surface electric potentials (SEP) at the interfaces of LB film/metals were also measured using a Kelvin probe. The SEP in the CuttbPc/Al decreases and eventually approaches a saturated value of -1.0V as the film thickness increases, while the SEP in the CuttbPc/Au is nearly zero. Based on the experimental results and theoretical analysis, it was considered that the space-charge-induced electric field makes a main contribution to the second-harmonic generation at 1250nm in the CuttbPc/Al film. 相似文献
2.
运用热刺激放电、表面电位衰减和电光效应的检测等手段,对主客体掺杂型非线性光学聚合物驻极体DR1/PMMA膜中空间和偶极电荷的相互作用特性进行了研究.结果表明,在极化后的样品中,被样品表面或体内的各类陷阱捕获的大部分空间电荷所处的陷阱能级高于极性生色团分子的定向排列产生的偶极电荷的束缚能级,空间电荷对偶极电荷有强烈的束缚作用.空间电荷衰减将导致材料内的电场分布发生变化,并引起极性生色团分子的松弛.空间电荷稳定性决定着偶极电荷的寿命.
关键词: 相似文献
3.
采用磁控溅射技术沉积制铝/贫铀/铝(Al/DU/Al)、金/贫铀/金(Au/DU/Au) "三明治" 薄膜样品. 利用高分辨扫描电镜、 X射线衍射仪、X射线光电子能谱仪、 扫描俄歇微探针对Al/DU/Al, Au/DU/Au样品的Al/DU, Au/DU界面行为进行表征与研究. 结果表明: 沉积态DU层以柱状晶生长; Al/DU界面扩散明显, 物理扩散过程中伴随着Al, DU化学反应形成Al2U, Al3U金属化合物; 金属化合物的形成导致界面处Al 2p电子结合能向高能端移动, U 4f电子向低能端移动; 微量O在Al/DU界面处以Al2O3及铀氧化物形式存在; DU镀层中以铀氧化形式存在; 沉积态的Au/DU界面扩散为简单的物理扩散, 团簇效应导致Au/DU界面处Al 2p, U 4f电子结合能均向高能端移动; 在Au/DU界面及DU镀层中, 微量O以铀氧化物形式存在; Al/DU界面扩散强于Au/DU; 相同厚度的Al, Au保护镀层, Al镀层保护效果优于Au镀层.
关键词:
Al/DU界面
Au/DU界面
磁控溅射
界面扩散 相似文献
4.
运用热刺激放电、表面电位衰减和电光效应的检测等手段,对主客体掺杂型非线性光学聚合物驻极体DR1/PMMA膜中空间和偶极电荷的相互作用特性进行了研究.结果表明,在极化后的样品中,被样品表面或体内的各类陷阱捕获的大部分空间电荷所处的陷阱能级高于极性生色团分子的定向排列产生的偶极电荷的束缚能级,空间电荷对偶极电荷有强烈的束缚作用.空间电荷衰减将导致材料内的电场分布发生变化,并引起极性生色团分子的松弛.空间电荷稳定性决定着偶极电荷的寿命 相似文献
5.
应用分光光度计测量Te/TeO2-SiO2复合薄膜的透射光谱和吸收光谱, 在480nm附近观察到Te颗粒引起的等离子体共振吸收峰; 采用Z扫描技术研究了共振(激发波长为532 nm)和非共振情况下(激发波长1064 nm) 不同电位制备薄膜的Te颗粒状态与复合薄膜的三阶非线性极化率的关系. 基于有效介质理论对复合薄膜的三阶非线性效应进行分析, 研究Te颗粒大小对Te/TeO2-SiO2复合薄膜的非线性光学性质的影响及其产生机理. 结果表明薄膜制备过电位增大, Te的粒径减小, 颗粒数量多, 颗粒分布趋于均匀, 使得金属颗粒的表面等离子体共振峰红移, 吸收强度增强, 导致三阶非线性光学效应增强, χ(3)由1064 nm的5.12×10-7 esu增大为532 nm的8.11×10-7 esu.
关键词:
碲
二氧化碲
复合薄膜
三阶非线性 相似文献
6.
用两线法和四线法对球磨合成后热处理的Nd0.7Sr0.3MnO3陶瓷样品的电脉冲诱导电阻转变(EPIR)效应进行了测试.结果表明:在Nd0.7Sr0.3MnO3块体中用四线法测得的I-V曲线为非线性,说明Nd0.7Sr0.3MnO3样品在晶(相)界处存在空间电荷层和界面电阻.但用四线法测量EPIR效应时,没有EPIR效应发生,表明晶(相)界处的空间电荷层和肖特基势垒不能产生EPIR效应;对同一样品采用直流两线法测量,其I-V曲线也为非线性,但却发生明显的EPIR效应.说明在Nd0.7Sr0.3MnO3陶瓷中发现的EPIR效应起源于样品与电极之间的接触界面,块体内的晶(相)界处虽能产生相似I-V特性,但却不能发生EPIR效应.
关键词:
电脉冲诱导电阻转变(EPIR)
亚锰酸盐
空间电荷层
I-V非线性')" href="#">I-V非线性 相似文献
7.
8.
采用纳米球蚀刻法制备了Au纳米颗粒阵列.并通过扫描电子显微镜观测了其表面形貌,表明三角形的Au纳米颗粒呈阵列状分布.采用Z扫描方法(800 nm, 50 fs)测量了Au纳米颗粒阵列的三阶非线性光学特性.在较小的激发功率下,结果呈现出双光子吸收效应,随着激发功率不断增加,出现了双光子吸收饱和的过程;非线性折射则呈现出自散焦效应.这种高效率的非线性响应机理使得该种Au纳米颗粒阵列在高速全光开关中有潜在的应用价值.
关键词:
纳米球蚀刻技术
Au纳米颗粒
三阶光学非线性 相似文献
9.
采用金属有机化学气相沉积(MOCVD)技术在蓝宝石衬底上制备出晶体质量较好的透明导电的ZnO/Au/ZnO(ZAZ)多层膜,其中,Au夹层是通过射频磁控溅射的方法获得。通过对Au夹层进行不同温度的退火处理,研究了Au层退火温度对ZAZ多层膜的结构特性、电学性能和光学特性的影响。利用原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射(XRD)仪、霍尔效应测试和透射谱分析等测试手段对ZAZ多层膜的性质进行了分析。测试结果表明,在200 ℃下对Au夹层进行快速退火处理,多层膜的结构、电学和光学性质达到最优,表面等离子体效应也更明显。其中,XRD(002)衍射峰的半高宽为0.14°,电阻率为2.7×10-3 Ω·cm,载流子浓度为1.07×1020 cm-3,可见光区平均透过率为75.3%。 相似文献
10.
利用一维实验,模拟了惯性约束聚变中烧蚀层中冲击波传输和多次冲击追赶过程.针对聚苯乙烯材料(CH)容易被X射线离化的问题,通过较详细的数值模拟,分析了用Au和Cu做阻挡层对冲击波信号的影响.利用两种不同的辐射源,研究了辐射源两个台阶强度变化对两次冲击信号的影响.经过分析,使用在Al基底上面加厚度为5 μm的Au膜以挡X射线的办法,获得了单次冲击在CH材料中加载和减速的清晰条纹图.利用在Al基底上加厚度为2 μm的Au膜和厚度为3 μm的Cu膜的方法,获得了两次冲击在CH材料中加速、减速和二次加载的条纹图.实
关键词:
光学诊断
冲击波调速
离化效应 相似文献
11.
T. Götz M. Buck C. Dressler F. Eisert F. Träger 《Applied Physics A: Materials Science & Processing》1995,60(6):607-612
Optical Second Harmonic Generation (SHG) by metal clusters has been investigated. For this purpose clusters were generated by the deposition and nucleation of metal atoms on a LiF(100) single crystal surface under ultrahigh vacuum conditions. The size and shape of the metal particles was characterized by optical transmission spectroscopy. The SHG intensity was detected in situ as a function of cluster size during the nucleation. Fundamental wavelengths of =1064 and 532 nm were used and the SHG signal was measured for different polarization combinations of the incident and registered light. SH radiation is detectable for particles as small as approximately 1 nm. The signal grows monotonically as a function of particle size, passes a maximum and finally drops off. This behavior is discussed in terms of resonant enhancement of the signal by surface plasmon excitation and changes of
(2) as a function of particle size and shape. In further experiments the chemisorption of oxygen on the surface of the metal particles was studied. The SH signal decreases as a function of oxygen coverage and amounts to only about 15% of the initial value upon chemisorption of one monolayer. This indicates that the SH signal originates almost exclusively from the surface of the clean clusters and that higher order bulk contributions are negligible. 相似文献
12.
研究了芪盐在不同表压下制备的LB膜的二阶光学非线性。测量得到在低表压增强的二次谐波信号。对比芪盐的π-A曲线和透射光谱,认为在LB膜中芪盐以固相态存在,低表压时的固相态聚集体的吸收峰351nm使四阶非线性极化率X^(4)(-2ω:ω,ω,ω,-ω)产生共振强,四阶光学非线性现象对二次谐波信号产生影响。 相似文献
13.
14.
采用线性吸收谱和二次谐波产生技术研究了温度对具有中心对称结构的稀土夹心双萘酞菁化合物LB膜光学特性及其LB膜结构的影响。研究发现,加热可以使其LB膜的结构及分子间的相互作用发生变化,并形成J聚集体,从而使得吸收峰发生红移。稀土夹心双萘酞菁化合物约在40 ℃时其二次谐波信号有一个极小值,约在65 ℃时该化合物发生相变,使得二次谐波信号产生极大值,二次谐波信号最小时温度可高达180 ℃,说明该化合物的化学结构较为稳定。 相似文献
15.
半花菁衍生物LB膜的非线性光学性能研究 总被引:3,自引:1,他引:2
本文利用二次谐波产生、紫外-可见吸收光谱、Ⅱ-A曲线等方法,探讨了四种分子结构相近的半花菁染料衍生物LB膜的非线性光学性能。研究了它们的分子结构与β值大小的关系,分析了引起β值变化的主要原因,证实了极性基团的强弱顺序。并讨论了LB膜中聚集效应程度不同的原因。通过光学二次谐波信号强度与膜层数的关系,对比了样品的成膜性能。 相似文献
16.
We investigated the formation mechanism of nanoporous alumina in the electrochemical reaction of aluminium with oxalic acid solution in terms of the pinning effect of Fermi level at the metal–oxide interface. On the Al metal surface, the image potential state pins the standing mode of collectively excited surface electrons and the evanescent wave forms the plasmon mode, which can be reflected in oxide barrier formation. A nanoporous alumina thin film with an amorphous phase oxide layer on the Al surface can enhance light absorption at a shorter wavelength than 382 nm and provide strong Fabry–Perot oscillation in photoreflectance. The cathodoluminescence spectra show the surface plasmon mode as a consequence of the self-ordered oxide nanopores. The Kretschmann configuration of an attenuated total reflection set-up for prism/oxalic solution/Al interface, which also provides a prism-coupled surface plasmon and forms oxide nanopores on the Al surface via a laser-enhanced anodization process. 相似文献
17.
Two different ways to form monolayers and LB films (surface film and subphase film) of the complex have been used, where a novel amphiphile containing Schiff base as a headgroup was used as a ligand. the monolayer behavior at the air/water interface was characterized by π-A isotherms and two-dimensional molecular orientation of alkyl chains in LB films and thermal stability were measured by polarized and variable temperature FTIR transmission spectra, indicating that the LB film of the novel amphiphile and its copper(II) complex are very stable as well as stearic acid. Because incorporating the metal ion into the monolayer makes it more condensed, thermal stability of the LB film was enhanced. as can be compared from their structure and properties, subphase films are superior to surface films. 相似文献
18.
The asymmetric distributions of surface optical second harmonic generation
(SHG) through azimuthally angular scans of (111) silicon wafers on which
thin silver films were deposited, have been detected with different
polarizations of output beams. On account of the inversion symmetry of
silicon crystals, the SHG for the Ag/Si system is mainly contributed by the
silver film and the silicon surface. In this work, we found that the
interface strain implies an asymmetric intensity variation of SHG with
respect to the surface azimuthal angles as an ultra thin Ag film is
deposited on silicon wafers. This asymmetric behavior is prominent as the
deposited silver layer is heated so that the continuous film aggregates to
become granular nanoparticles. Similar changes of the surface asymmetric SHG
are observed for a bare Si wafer imposed upon by an external force. 相似文献
19.
A. Melnikov O. Krupin U. Bovensiepen K. Starke M. Wolf E. Matthias 《Applied physics. B, Lasers and optics》2002,74(7-8):723-727
The magnetization of 10-nm Gd films on W (110) has been investigated with second-harmonic generation (SHG). We observed a
strong second-harmonic (SH) yield, which we attribute to resonance enhancement by the well-known Gd (0001) d-like surface
state above the Fermi level. Since this state is spin-polarized it enhances the magnetic SHG contrast. The contrast, the relative
phase between odd and even SH fields, and the amplitude ratio of these fields depend strongly on wavelength, which confirms
the resonance enhancement. Further proof is provided by the fact that oxidation of the Gd surface reduces the SH yield by
an order of magnitude.
Received: 16 October 2001 / Revised version: 21 March 2002 / Published online: 11 June 2002 相似文献
20.
Second-harmonic generation (SHG) excited by a p-polarized terahertz wave interacting with AlGaAs/GaAs step quantum wells (STQW’s) is investigated on the basis of the microscopic nonlocal response theory. The numerical results show that there are two resonant peaks in the energy reflection spectrum of the SHG, whose position and amplitude are tunable via the structural parameters of the STQW’s and the incident optical intensity. It is clarified that the spatial nonlocality of the linear and second-order nonlinear optical responses can lead to a blueshift of the second-harmonic spectra, while the third-order nonlinearity can induce a spectral redshift. Furthermore, an optimal STQW is presented, for obtaining the largest SHG signal and observing the SH spectra by experiment. 相似文献