Coulomb blockade double-dot Aharonov-Bohm interferometer: Harmonic decomposition of the interference pattern

For the solid-state double-dot interferometer, the phase shifted interference pattern induced by the interplay of inter-dot Coulomb correlation and multiple reflections is analyzed by harmonic decomposition. Unexpected result is uncovered, and is discussed in connection with the which-path detection and electron loss. (C) 2009 Elsevier B.V. All rights reserved.

Shubnikov de Haas oscillations of a two-dimensional electron gas in a modulation-doped Zn0.80Cd0.20Se/ZnS0.06Se0.94 single quantum well

The magnetotransport properties of the two-dimensional (2D) electron gas confined in a modulation-doped Zn0.80Cd0.20Se/ZnS0.06Se0.94 single quantum well structure were studied at temperatures down to 0.35 K in magnetic fields up to 7.5 T. Well resolved 2D Shubnikovde Haas (SdH) oscillations were observed, although the conductivity of the sample in the as grown state was dominated by a bulk parallel conduction layer. After removing most of the parallel conduction layer by wet chemical etching the amplitude and number of SdH oscillations increased. From the temperature dependence of the amplitude the effective mass of the electrons was estimated as 0.17 m(0). Copyright (C) 1996 Published by Elsevier Science Ltd

Electron injection by a nanowire in the bubble regime

The triggering of wave-breaking in a three-dimensional laser plasma wake (bubble) is investigated. The Coulomb potential from a nanowire is used to disturb the wake field to initialize the wave-breaking. The electron acceleration becomes more stable and the laser power needed for self-trapping is lowered. Three-dimensional particle-in-cell simulations were performed. Electrons with a charge of about 100 pC can be accelerated stably to energy about 170 MeV with a laser energy of 460 mJ. The first step towards tailoring the electron beam properties such as the energy, energy spread, and charge is discussed. (C) 2007 American Institute of Physics.

Anomalous behaviour of photorefractive grating erasure owing to existence of both negative and positive carriers

In LiNbO3:Fe, anomalous behaviour of grating erasure is observed with different wavelenghts, i.e. rapid grating erasure in the short wavelength range, which deviates from the results predicted by the electron transport band model. The deviation is related to the coexistance of electrons and holes in photorefraction, and charge-transfer process including electrons and hole has been proposed. The electron and hole contributions to photo-excitation coefficient S of the Fe centre on the wavelength.

Yb：YAG晶体的红外闪烁特性

用脉冲电子束激发测量了不同Yb^3+掺杂浓度的Yb：YAG晶体的红外(IR)闪烁发光性能。Yb：YAG晶体的IR闪烁发光具有高的光产额和长的衰减时间，但存在浓度猝灭效应和温度依赖关系。Yb：YAG晶体的IR闪烁性能还与晶体品质有关，相同掺杂浓度的Yb：YAG晶体，品质优异的会获得更高的光产额。这一初步的研究成果表明，部分掺Yb^3+晶体有可能用于医学成像装置。

Precipitation of Ge nanoparticles from GeO2 glasses in transmission electron microscope

We show, using spatially resolved energy loss spectroscopy in a transmission electron microscopy (TEM), that GeO2 and GeO2-SiO2 glasses are extremely sensitive to high energy electrons. Ge nanoparticles can be precipitated in GeO2 glasses efficiently by the high-energy electron beam of a TEM. This is relevant to TEM characterization of luminescent Ge nanoparticles in silicate glasses, which may produce artificial results. (C) 2005 American Institute of Physics.

Effects of CO2 laser conditioning of the antireflection Y2O3/SiO2 coatings at 351 nm

Y2O3/SiO2 coatings were deposited on fused silica by electron beam evaporation. A continuous wave CO2 laser was used to condition parts of the prepared samples at different scanning speeds in the air. LAMBDA 900 spectrometer was used to investigate the changes of the transmittance and residual reflection spectrum. A Nomarski microscope under dark field was used to examine the changes of the micro defect density. The changes of the surface roughness and the microstructure of the film before and after conditioning were investigated by AFM and X-ray diffraction, respectively. We found that laser-induced damage threshold (LIDT) of the films conditioning at 30 mm/s scanning speed was increased by more than a factor of 3 over the thresholds of the as-deposited films. The conditioning effect was correlated with an irradiation-induced decrease of the defect density and absorption of the films. (c) 2005 Elsevier B.V. All rights reserved.

Effect of microstructure of TiO2 thin films on optical band gap energy

TiO2 coatings are prepared on fused silica with conventional electron beam evaporation deposition. After annealed at different temperatures for four hours, the spectra and XRD patterns of TiO2 thin film are obtained. XRD patterns reveal that only anatase phase can be observed in TiO2 coatings regardless of the different annealing temperatures, and with the increasing annealing temperature, the grain size gradually increases. The relationship between the energy gap and microstructure of anatase is determined and discussed. The quantum confinement effect is observed that with the increasing grain size of TiO2 thin film, the band gap energy shifts from 3.4 eV to 3.21 eV. Moreover, other possible influence of the TiO2 thin-film microstructure, such as surface roughness and thin film absorption, on band gap energy is also expected.

氧分压对ZrO2薄膜激光损伤阈值的影响

在不同的氧分压下用电子束热蒸发的方法制备了ZrO2薄膜。分别通过X射线衍射、光学光谱、热透镜技术、抗激光辐照等测试，对所制备样品的微结构、折射率、吸收率及激光损伤阈值进行了测量。实验结果表明，薄膜中晶粒主要是四方相为主的多晶结构，并且随着氧分压的增加，结晶度、折射率以及弱吸收均逐渐降低。薄膜的激光损伤阈值开始随着氧分压增加从18．5J／cm^2逐渐增加，氧分压为9×10^-3Pa时达到最大，值为26．7J／cm^2，氧分压再增加时则又降低到17．5J／cm^2。由此可见，氧分压引起的薄膜微结构变化是ZrO

倾斜角沉积技术制备ZnS双折射雕塑薄膜

使用倾斜角沉积（GLAD）的电子束蒸发技术，制备了倾斜角度在60°～85°之间的ZnS双折射雕塑薄膜（STF）。使用X射线衍射（XRD）和扫描电镜（SEM）检测了ZnS薄膜的结晶状态和断面形貌，使用Lamda-900分光光度计测量了薄膜在不同的偏振光入射时的透过率。研究发现，室温下倾斜沉积ZnS薄膜断面为倾斜柱状结构，且薄膜的结晶程度不高。在相同的监控厚度时，随倾斜角度增大，沉积到基片上的薄膜厚度逐渐变小，但仍然大于余弦曲线显示的理论厚度。根据偏振光垂直入射时薄膜的透过光谱计算了不同角度沉积的薄膜的折射率

Study of Al2O3/MgF2 HR coatings at 355 nm

With the present work we tried to study the effective methods to improve the laser-induced damage threshold (LIDT) and reflectance of HR coatings at 355 nm. The work presented in this paper wits part of an ongoing study about vacuum annealing. It was dedicated to study the effects Of Vacuum annealing with different temperature gradients on the structure, optical properties and laser-induced damage threshold (LIDT) of 355nm Al2O3/MgF2HR coatings. A number of samples were prepared by electron beam evaporation using the same deposition process with an optimal deposition temperature of 280 degrees C. After deposition, samples were annealed in the coating chamber for 3 h with different temperature gradients. Morphologies of the samples were observed by Leica-DMRXE. Microscope, Structure of the samples had been characterized by X-ray diffraction (XRD). Transmittance and reflectance of the samples were measured by Lambda 900 Spectrometer, The LIDT of the samples was measured by a 355 nm Nd:YAG laser with a pulse width of 8 ns. It was found that the temperature gradient of vacuum annealing had significant effects on the morphology, structure, absorption, and LIDT of the samples, (c) 2005 Elsevier Ltd. All rights reserved.

电子束蒸发制备平板偏振膜激光损伤特性研究

采用电子束蒸发沉积技术制备了平板偏振膜。用Lambda900分光光度计测试了其光学性能。在中心波长1053nm处P偏振光的透过率Tp〉98％，S偏振光的透过率Ts〈0．5％，消光比T，／瓦〉200：1，带宽约为20nm。用波长1064nm，脉宽12ns的脉冲激光进行损伤阈值测试，获得P偏振光的损伤阈值为17．2J／cm^2，S偏振光的损伤阈值为19．6J／cm^2。用Nomarski显微镜对薄膜的损伤形貌进行观察，并用Alpha-500型台阶仪对损伤深度进行测试。结果表明，P偏振光的激光损伤为界面损伤与缺

HfO2薄膜的结构对抗激光损伤阈值的影响

利用蒸发氧化铪和离子辅助蒸发金属铪反应沉积氧化铪薄膜，对两种工艺下制备的氧化铪薄膜进行光学和结构以及激光损伤特性的研究，实验结果表明，用金属铪反应沉积的氧化铪薄膜不仅结构均匀，并且具有较高的激光损伤阈值．文章对损伤阈值和薄膜的结构及光学特性之间的关系进行了讨论。

脉冲激光辐照光学薄膜的缺陷损伤模型

建立了缺陷吸收升温致薄膜激光损伤模型，该模型从热传导方程出发，考虑了缺陷内部的温度分布以及向薄膜的传导过程，通过引入散射系数简化了Mie散射理论得出的吸收截面．对电子束蒸发沉积的ZrO2：Y2O3单层膜进行了激光破坏实验，薄膜样品的损伤是缺陷引起的，通过辉光放电质谱法对薄膜制备材料的纯度分析发现材料中的主要杂质元素为铂，其含量为0．9％．利用缺陷损伤模型对损伤过程进行了模拟，理论模型和实验结果取得了较好的一致性．

1064nm倍频波长分离膜的制备与性能研究

通过对主膜系添加匹配层并借助计算机对膜系进行优化，设计出结构规整、性能优良的1064ilm倍频波长分离膜。用电子束蒸发及光电极值监控技术在K9玻璃基底上沉积薄膜，将样品置于空气中在260℃温度下进行3h热退火处理。然后用Lambda 900分光光度计测量了样品的光谱性能；用表面热透镜(STL)技术测量了样品的弱吸收值；用调Q脉冲激光装置测试了样品的抗激光损伤阈值(LIDT)。实验结果发现，样品的实验光谱性能与理论光谱性能有很好的一致性。退火前后其光谱性能几乎没有发生温漂，说明薄膜的温度稳定性好；同时退火使