共查询到20条相似文献,搜索用时 15 毫秒
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Air, liquid and solid sample interferometric gaps of the same thickness and simultaneously enclosed in a wedge interferometer are used to produce fringes of equal chromatic order. A mica sample of dimensions 2×5 mm2 and an immersion liquid of the same refractive index are used. A single shot interferogram containing fringes in the three gaps is sufficient to deduce the needed experimental data. Locations of fringe maxima are introduced in a numerical procedure to retrieve the sample and liquid refractive indices across the visible spectrum. The numerical procedure is based on a simple dispersion function of wavelength and wavenumber. A modified two-term Sellmeier dispersion formula has been used for fitting the experimental data and deducing the needed dispersion parameters. 相似文献
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Media with negative index of refraction are discussed briefly within Sellmeier model. In particular, dispersion of light waves is found to be anomalous and the corresponding coefficient of material dispersion is found to be negative. In addition, the group index becomes negative. 相似文献
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透射式微分干涉显微镜测量光纤折射率分布 总被引:1,自引:1,他引:0
提出一种由两组偏光棱镜组成的透射式微分干涉系统,用来测量光纤的折射率分布。系统利用旋转检偏器对测量光束进行调制,从相位分布和光程分布中计算出折射率分布。介绍了测量原理、测量公式、系统组成及典型应用。用该系统对光纤折射率进行实际测量,给出渐变折射率光纤的二维分布,及折射率沿轴向的分布图,同时还在NR 9200光纤测试仪上进行了测试。结果表明,系统原理正确,结构简捷,具有足够分辨率和测量精度,抗干扰能力强,不破坏光纤,还可测量包层和芯层的直径,发现光纤加工过程中的缺陷,特别适合加工、焊接等工艺过程中的检测。 相似文献
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在时域中求解得到,光路中存在色散介质的情况下,白光双光束干涉光强度.由此证明了:用白光干涉法测量得到的是白光在色散介质中的群折射率,而并非相关报道中认为的折射率;讨论了介质厚度及色散对于涉条纹的可见度和干涉条纹显现时动镜移动范围的影响.上述结论得到了实验验证. 相似文献
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Light refraction in a medium results from energy exchange between the medium and the magnetic field of the light. Formulas of refractive index, that is, the ratio of light speed in vacuum to light speed in the medium, were derived with the inductor model of electron cloud and the law of energy conservation. Refractive indices of several media were calculated using the formulas derived, and the calculated results are in agreement with the results measured. The anisotropy and the nonlinearity of the refractive index are explained with the theory described in this work. 相似文献
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由光的波动方程证明,若介质为旋光物质,则其极化率张量χ一定有非对角对称的共轭虚元素,并导出了旋光晶体的寻常折射率no与左旋光折射率nL和右旋光折射率nR之间的关系.将理论分析结果与实验数据相对照,结果完全吻合. 相似文献
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常用的测量折射率的方法如偏向角法、自准直法、临界角法、 V棱镜法等,这些方法通常需特制三棱镜与待测件。待测样品不一致且过程复杂,测试定标周期长,难于自动化。为了保证待测材料的完整及实现自动化测量,进行了基于平行平板的折射率非接触测量的尝试。运用该方法进行折射率的测量,不需特制三棱镜并且待测件与待测样品一致。分析表明,通过选择合适的测量角度,该方法旋转角度精度为a=0.003(即10),导轨精度为L=0.000 8 mm,平行平板厚度测量精度为d=0.001 mm。 相似文献
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Using the phenomenon of total internal reflection and a beam splitting device, a technique of simultaneous phase-shift interferometry is proposed for measuring the full-field refractive index. Because this method applies a beam splitting device that mimics the characteristics of beam splitting and phase modulation, four interferemetric images of various phase distributions can be simultaneously captured. Therefore, this setup can avoid errors caused by non-simultaneous capturing of images and offers the benefits of high stability, ease of operation, and real-time measurement. Furthermore, using the phenomenon of total internal reflection, the phase difference between p- and s-polarized light varies considerably with the refractive index of a tested specimen. This can substantially increase the measurement resolution. The feasibility of this method is verified using an experiment, and the measurement resolution can be higher than 3.65 × 10−4 RIU. 相似文献
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温度对气体折射率的非线性影响 总被引:3,自引:2,他引:1
对测量群折射率的迈克耳孙白光干涉技术进行了改进,采用光栅线位移传感器提高反射扫描镜的位移精度. 实验确定了空气折射率对温度的非线性曲线拟合方程,其拟合因子的精度达到10-5℃-1. 相似文献
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介绍了用准相干干涉法测量光纤群折射率的方法。通过准相干干涉定位 ,用精密光栅数显系统测长 ,由计算机采集并处理数据获得一段短光纤的光学长度 ,然后利用常规精密测长手段测得其几何长度 ,从而得到光纤的群折射率。实验结果及误差分析得出 :测量不确定度优于 7× 10 -5(2σ)。 相似文献
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A closed four-level system in atomic vapour is proposed, which is made to possess left handedness by using the technique of quantum coherence. The density matrix method is utilized in view of the rotating-wave approximation and the effect of a local field in dense gas. The numerical simulation result shows that the negative permittivity and the negative permeability of the medium can be achieved simultaneously (i.e. the left handedness) in a wider frequency band under appropriate parameter conditions. Furthermore, when analysing the dispersion property of the left-handed material, we can find that the probe beam propagation can be controlled from superluminal to subluminal, or vice versa via changing the detuning of the probe field. 相似文献
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S. Y. El-Zaiat 《Optics & Laser Technology》2001,33(2)
Fringes of equal chromatic order are produced in air, immersion liquid and mica sample interferometric gaps. The three gaps are of the same thickness and simultaneously enclosed in a wedge interferometer. A single-shot interferogram contains fringes in the three gaps is sufficient to deduce the needed experimental data. A non-numerical procedure is used for determining the refractive indices of the immersion liquid and mica sample across the visible spectrum. There is no need for any numerical fitting stage nor for the application of any theoretical model concerning the dispersion behavior of the sample under test. A modified two-term Sellmeier dispersion formula has been used for fitting the experimental data and deducing the needed dispersion parameters. 相似文献
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本文对棱镜耦合法测波导衬底折射率进行了实验研究,在两种入射情况下,对石英玻璃、CaF_2、LiF衬底及C-813-8胶块进行了折射率测量,并得到有益的实验结果. 相似文献
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分析了掠入射法测定液体折射率实验中棱镜角的选择范围,提出了增加半荫视场可见度的途径,讨论了光源位置和棱镜选取对半荫视场分界线可见度的影响,得出了实验室常用棱镜的选择方案. 相似文献