共查询到20条相似文献,搜索用时 15 毫秒
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An integrated-optical strip-waveguide is directly written into the surface of a planar polymer substrate by an excimer laser beam. The mode field distribution, the surface refractive index and the refractive index depth profile of the waveguide have been examined. The intensity distribution of the mode field strongly depends on the refractive index depth profile, on the light coupling conditions and on the waveguide fabrication process parameters. 相似文献
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The depth dependent UV-light absorption profile of GaN nanorods with different lattice arrays and filling factors was studied using finite-difference time-domain (FDTD) methods. By comparing to the results from Lambert-Beer's law with Maxwell-Garnett effective medium theory, we identified the quantitative contribution from nano-scattering effect on the light absorption in the nanorod arrays. The FDTD study of graphical 3D profile of light absorption and electric field intensity was parallelly conducted to investigate the origin of the nano-scattering. We found that the coupled electric field in the gap regions led to the larger absorption cross-section of the nanorod arrays, which is attributed to the distorted depth profile of the light absorption. 相似文献
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This work reports the construction of a single-sided magnet generating a sensitive volume with adjustable curvature. It is useful to profile cylindrical samples with high depth resolution. The sensor geometry is based on the Profile NMR-MOUSE, which generates a parabolic field profile with a quadratic coefficient that decreases with the distance from the magnet surface. Such field profiles approximate cylinder walls within limited angular range with negligible deviation. Then, by varying the working depth, shells of different diameter in the sample can be matched. Simulation and experiments conducted on phantoms confirm that a depth resolution of about 35 μm can be obtained. The sensor was used to profile the structure of a cylindric air spring bellows with high resolution. Besides resolving the fiber layers used to reinforce the rubber matrix, the ingress of hexane was detected via T 2 changes of the material. 相似文献
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Mateusz Krzyzosiak Zheyu Huang Shiping Feng Ryszard Gonczarek 《Physica C: Superconductivity and its Applications》2010,470(7-8):407-414
Within the framework of the kinetic energy driven superconductivity, the electromagnetic response in cuprate superconductors is studied in the linear response approach. The kernel of the response function is evaluated and employed to calculate the local magnetic field profile, the magnetic field penetration depth, and the superfluid density, based on the specular reflection model for a purely transverse vector potential. It is shown that the low temperature magnetic field profile follows an exponential decay at the surface, while the magnetic field penetration depth depends linearly on temperature, except for the strong deviation from the linear characteristics at extremely low temperatures. The superfluid density is found to decrease linearly with decreasing doping concentration in the underdoped regime. The problem of gauge invariance is addressed and an approximation for the dressed current vertex, which does not violate local charge conservation is proposed and discussed. 相似文献
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A numerical method of determining depth profile of
thermo-physical parameters of an inhomogeneous sample is presented. By
dividing the inhomogeneous material into number of sublayers in which each
single layer can be treated as homogeneous, the thermal-wave field of the
material is obtained based on recurrence relations of thermophysical
parameters of each divided layer. A numerical algorithm of determining the
depth profile of thermophysical parameters in the continuously inhomogeneous
material under excitation of arbitrary beam size has been
demonstrated by a polynomial fitting process for three arbitrary generated
thermophysical profiles. 相似文献
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Hironobu Hori Keiko Tawa Kenji Kintaka Junji Nishii Yoshiro Tatsu 《Optical Review》2009,16(2):216-221
The fluorescence intensity of a sample placed on a metal grating pattern is enhanced due to excitation by the electric field
of the grating-coupled surface plasmon resonance (GC-SPR). The dependence of the enhancement on groove depth and surface profile
was studied with the aim of improving the sensitivity of fluorescence detection. The enhancement was found to depend on the
groove depth, with intensity most enhanced on grating substrate of about 20 nm depth, which produced an intensity about 30
times greater than that on a flat borosilicate glass substrate. Rigorous coupled wave analysis calculation showed that the
shape of the groove influenced GC-SPR, suggesting that controlling not only the depth but also the shape of the grating surface
profile can be an important factor in improving the sensitivity of detection by fluorescence microscopy. 相似文献
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Near-stoichiometric Ti:LiNbO3 strip waveguide with varied substrate refractive index in waveguide layer
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We report the near-stoichiometric Ti:LiNbO3 strip waveguides fabricated by vapour transport equilibration (VTE) at 1060 C for 12 h and co-diffusion of 4-8 μm wide, 115-nm thick Ti-strips. Optical studies show that these waveguides are monomode at 1.5 μm and have losses of 1.3 and 1.1 dB/cm for the TM and TE modes, respectively. In the waveguide width/depth direction, the mode field follows a Gauss/Hermite-Gauss profile. A secondary ion mass spectrometry study reveals that the Ti profile follows a sum of two error functions along the width direction and a complementary error function in the depth direction. Micro-Raman analysis shows that the Li-composition in the depth direction also follows a complementary error function. The mean Li/Nb ratio in the waveguide layer is about 0.98. The inhomogeneous Li-composition profile results in a varied substrate index in the guiding layer, and the refractive index profile in the guiding layer is given. 相似文献
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任意槽形金属光栅矢量模式理论的数值计算 总被引:1,自引:1,他引:0
本文根据任意槽形金属光栅的矢量模式理论,对正弦槽光栅和半椭圆槽光栅的情况进行了推导和数值计算。对任意入射方向和偏振态的入射场,计算了其衍射场的分布情况,并详细研究了光栅结构参数(光栅常数、槽宽、槽深等)对衍射场的影响。 相似文献
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针对浅海环境下声速剖面失配引起的匹配场处理器失配问题,提出了一种自适应匹配场定位算法在声速剖面时变环境下的实现方式。将先验声速剖面集简化为经验正交函数表示,结合蒙特卡洛方法与环境扰动约束算法对当下时刻的目标声源进行匹配场定位。本文以某次试验获取的连续20小时的声速剖面数据为研究对象,通过仿真试验对该算法进行验证,结果表明:在先验声速剖面集的半小时之后,利用自适应算法的距离和深度定位成功率较常规匹配场算法有较大提升,其中,深度正确定位概率相对较低。 相似文献
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瑞利判断与斯托列尔准则(兼论光学系统景深与清晰度法定焦精度) 总被引:2,自引:0,他引:2
本文根据圆孔菲涅耳衍射象点附近的振幅和光强空间分布,论证了瑞利判断与斯托列尔准则是统一的.指出应用光学中景深的概念存在问题,传统的用物理景深和几何景深相加来计算清晰度法定焦精度是不妥的. 相似文献
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《中国光学快报(英文版)》2017,(6)
The depth profile of electric-field-induced(EFI) optical rectification(OR) and EFI Pockels effect(PE) in a Si(110) crystal are investigated. The results show that EFI OR and PE signals are very sensitive to the electric field strength in the surface layers of the Si crystal. Theoretical formulas that include the electric field parameters and the widths of the space-charge region are presented and agreed very well with the experimental results. The experiments and simulations indicate that EFI OR and PE are potential methods for researching the surface/interface properties along the depth direction in centrosymmetric crystals such as Si. 相似文献
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A Buckminsterfullerene ion beam has been applied to the depth profiling of an alternating pure Pt and pure Co multilayer. Quantitative depth profiling was performed by secondary ion mass spectrometry (SIMS) with C60 ions using Pt-Co alloy films with different compositions. Relative sensitivity factors (RSFs) derived from a Pt39Co61 alloy film were used to convert an original depth profile to a composition depth profile. A severe interface artifact observed in the depth profile of a Pt/Co multilayer was quantitatively correlated with a gradual variation of matrix composition through the Pt/Co and Co/Pt interfaces by comparison with the depth profiling of an alloy multilayer film. Moreover, the interface artifact could be compensated by conversion of the profile to a composition profile using the same RSFs. The depth resolutions of a Pt/Co multilayer derived from the composition depth profile were much larger than the apparent interface widths measured from the original depth profile due to the nonlinear relationship between the Co and Pt ion intensities and their compositions. 相似文献
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Integral equations have been solved for the density profile of dipolar hard spheres against a hard, smooth wall in the presence of an electric field. This density profile was examined as a function of the bulk medium's temperature and density with different field strengths and field directions. It was found to depend primarily upon the competitive interactions of the field with the monolayer particles and the first outer shell with the monolayer particles.Supported by the ARGC. 相似文献
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Results of calculating the horizontal structure of acoustic field in the ocean with a canonical sound velocity profile are presented. The calculation is performed in the framework of geometrical acoustics by combining the fields of water-path rays at every point with allowance for their phases and amplitudes. The field distribution at a fixed depth is found to be not very informative: within a cycle length, it contains 1–3 maxima, which are mainly caused by the caustics present at the given depth. The width of caustics is ~0.1–1 km. Between the caustics, as well as in their absence, the field amplitude is much smaller than that in the regions of caustics and varies depending on the phases and amplitudes of rays arriving at a given point. The comparison of the calculated horizontal field structure with that obtained from full-scale measurements for the regions between the caustics is difficult because of the possible fluctuations of sound propagation conditions. 相似文献
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温跃层是反映海洋温度场的重要指标,针对太平洋中东部海域复杂多变的水文情况以及传统温跃层分析模式的局限性,本文基于BOA_Argo历史网格,通过BP神经网络,建立温度剖面的经验正交系数与海面遥感数据、少量深度处海水温度之间的非线性映射关系,实现海洋垂向温度剖面的实时反演,最后利用垂向梯度法获得海洋温跃层的相关参数。实验结果表明,相比于传统方法,该方法反演得到的跃层深度与测量值更加吻合,其中上层深度平均反演误差从10.3m下降到5.7m,下层深度平均反演误差从16.8m下降到8.8m。 相似文献
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