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31.
M.A. Shams El-Din M. KoerdtC. Wochnowski F. VollertsenA.M. Sadik 《Optics and Lasers in Engineering》2012,50(3):405-412
Polymeric integrated-optical waveguides are prepared in a planar polymer chip by UV-laser lithographic methods. The waveguide samples are irradiated by an excimer laser at a wavelength Λ=248 nm with various irradiation parameters (different fluencies and irradiation doses). Mach-Zehnder interferometer is employed and the refractive index depth profiles of the waveguide samples are obtained. This profile covers two regions having exponential and Gaussian shapes. The model field distributions strongly depend on the refractive index of each region. The mode field distribution and the effective mode indices for each region have been calculated on the basis of a theoretical model and the experimentally measured data. 相似文献
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33.
Combining high and low probability densities in intensity hybrids , we study some of their properties in double-slit setups. In particular, we connect to earlier results on beam attenuation techniques in neutron interferometry and study the effects of very small transmission factors, or very low counting rates, respectively, at one of the two slits. We use a “superclassical” modeling procedure which we have previously shown to produce predictions identical with those of standard quantum theory. Although in accordance with the latter, we show that there are previously unexpected new effects in intensity hybrids for transmission factors below a?10−4, which can eventually be observed with the aid of weak measurement techniques. We denote these as quantum sweeper effects, which are characterized by the bunching together of low counting rate particles within very narrow spatial domains. We give an explanation of this phenomenology by the circumstance that in reaching down to ever weaker channel intensities, the nonlinear nature of the probability density currents becomes ever more important, a fact which is generally not considered–although implicitly present–in standard quantum mechanics. 相似文献
34.
针对大口径离轴凸非球面面形检测的困难,本文将光学系统波像差检验技术与子孔径拼接干涉技术相结合,提出了凸非球面系统拼接检测方法。对该方法的基本原理和具体实现过程进行了分析和研究,并建立了合理的子孔径拼接数学模型。当离轴三反光学系统的主镜和三镜加工完成以后,对整个系统进行装调和测试,并依次测定光学系统各视场的波像差分布,通过综合优化子孔径拼接算法和全口径面形数据插值可以求解得到大口径非球面全口径的面形信息,从而为非球面后续加工和系统的装调提供了依据和保障。结合工程实例,对一口径为287 mm×115 mm的离轴非球面次镜进行了系统拼接测试和加工,经过两个周期的加工和测试,其面形分布的RMS值接近1/30λ(λ=632.8 nm)。 相似文献
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36.
When solving unsteady computational fluid dynamics problems in aerodynamics with a gridless method, a cloud of points is usually required to be regenerated due to its accommodation to moving boundaries. In order to handle this problem conveniently, a fast dynamic cloud method based on Delaunay graph mapping strategy is proposed in this paper. A dynamic cloud method makes use of algebraic mapping principles and therefore points can be accurately redistributed in the flow field without any iteration. In this way, the structure of the gridless clouds is not necessarily changed so that the clouds regeneration can be avoided successfully. The spatial derivatives of the mathematical modeling of the flow are directly determined by using weighted least‐squares method in each cloud of points, and then numerical fluxes can be obtained. A dual time‐stepping method is further implemented to advance the two‐dimensional Euler equations in arbitrary Lagarangian–Eulerian formulation in time. Finally, unsteady transonic flows over two different oscillating airfoils are simulated with the above method and results obtained are in good agreement with the experimental data. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
37.
Atom interferometry is a rapidly advancing field and this Letter proposes an experiment based on existing technology that can search for new short distance forces. With current technology it is possible to improve the sensitivity by up to a factor of 102 and near-future advances may be able to rewrite the limits for forces with ranges from 1 mm to 100 m. 相似文献
38.
Lucas P. Tendela Alejandro FedericoGuillermo H. Kaufmann 《Optics and Lasers in Engineering》2011,49(2):281-284
This paper presents an interferometric measurement of the out-of-plane deflections produced by a piezoelectric transducer, manufactured by thick-film deposition of a ceramic paste over an alumina substrate, when is subjected to a DC electric voltage. It is shown that a digital speckle pattern interferometer with an incorporated phase-shifting facility allows the measurement of nanometer displacements generated by the piezoelectric device. These measurements are used to evaluate the effective piezoelectric charge constant along the polarization direction (d33)eff that characterizes the thick-film transducer. 相似文献
39.
Fast growing technology and requirements for testing of different types of materials and devices require new methods and systems
for investigation of their parameters. Among the quantities of high interest are shape, deformation, roughness, local materials
constants, displacement, and strain fields of elements under load. In the paper, we present novel solutions for digital holographic
cameras, which allow for remote monitoring and measurement of the above mentioned quantities at small mechanical objects or
at restricted areas of interest at big structures. The systems have compact design, “black box” measurement approach, and
allows for fast and accurate measurements performed directly at the element and often in outdoor environment. The principles
of digital and optoelectronic reconstruction and phase manipulation are described together with the exemplary measurement
results obtained by means of the cameras presented. 相似文献
40.
对作者所提出的无干涉条纹直接电场重构测量飞秒脉冲的振幅和相位的新方法作出进一步理论分析,并通过实验测量说明该方法的优越性.该方法克服了传统的SPIDER方法的弊病,能得到一组无干涉条纹的图像,排除传统方法必须使用傅里叶变换滤波消除干涉条纹而引进的系统误差,使得该方法能够采用较简便设备且能较准确测量飞秒脉冲强度轮廓和相位.最后给出同一条件下新方法和传统SPIDER方法分别重构的脉冲强度自相关曲线与实验测量结果的比较,以说明新方法的有效性和优越性. 相似文献