共查询到15条相似文献,搜索用时 0 毫秒
1.
The effect of magnetic field on temperature and temperature profile of diffusion flame is investigated by using circular grating Talbot interferometer. Talbot interferometric fringes are recorded for diffusion flame generated by butane torch burner, in the absence of magnetic field, in the presence of uniform magnetic field, upward-decreasing and upward-increasing magnetic field. Analysis of recorded interferogram reveals that the temperature of the flame is increased under the influence of the upward-decreasing magnetic field and flame temperature is decreased under the influence of upward-increasing magnetic field. Uniform magnetic field has a negligible effect on temperature of the flame. 相似文献
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In this paper we have investigated the utility of Lau phase interferometer with linear gratings and white light source to measure temperature and temperature profile of an axisymmetric flame. The temperature measured using Lau phase interferometer is in good agreement with the temperature measured with thermocouple and datalogger. Details of theoretical analysis and experimental investigation are presented. 相似文献
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In this study, channel waveguides fabricated in photopolymer films by direct-writing using a low-power CW laser, are used as phase objects in a simple plane-wave diffraction setup, and the refractive index modulation profiles of the waveguides are characterized using the recorded diffraction patterns. Index profiles are modeled by piece-wisely combining two Gaussian functions representing the central and the tail regions. Measured diffraction patterns are matched with patterns generated using the model. This simple model makes it possible to design various channel waveguides embedded into polymer substrates. The proposed model is tested on three distinctive waveguide profiles written on the same Acrylamide/Polyvinyl Alcohol based photopolymer with different exposures. 相似文献
4.
This paper is devoted to the study on measurement of refractive index profile of graded-index polymer optical fiber (GI-POF) by light scattering. Using Generalized Airy theory and Debye series of an inhomogeneous cylinder, the scattering intensity distributions are obtained of Airy structure of rainbows for different refractive index profile. The results show that positions of Airy peaks depend closely on refractive index profile of GI-POF. Since each order of rainbow penetrates it to different depths, such methods could be used to provide information of the refractive index profile of GI-POF. For GI-POF with given diameter, positions of Airy peaks of rainbows are simulated as a function of refractive index profile, which can be used to inverse unknown parameters of refractive index profile. The least square method is used in inversion of refractive index profile with the given refractive index of the cladding. The results obtained agree with theoretical values with high precision. The method has the advantages of non-instructive and on-line measurement, and can be used for the measurement of other inhomogeneous droplets. 相似文献
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Real-time measurement of glucose concentration and average refractive index using a laser interferometer 总被引:4,自引:0,他引:4
This study presents a non-destructive, highly precise optical metrology system for measuring the average refractive index of a liquid solution such that its glucose concentration can be derived. The metrology system is employed to measure the average refractive indices of samples with known glucose concentrations ranging from 0 to 200 g/l. By applying a regressional analysis technique to the experimental results, an analytical expression is derived to describe the relationship between the refractive index and the glucose concentration. An excellent agreement is observed between the experimentally determined values of the glucose concentration and the analytically derived results. For an assumed laser interferometer resolution of 1 nm, the measurement resolution of the proposed metrology system is found to be at least F=0.05 g/l, which is significantly better than that of F=2 g/l obtained using the polarimetric glucose sensor presented by Lo and Yu [A polarimetric glucose sensor using a liquid-crystal polarization modulator driven by a sinusoidal signal. Opt Commun, 2006; 259: 40–8]. 相似文献
6.
《Journal of Electrostatics》2014,72(4):322-329
A number of methods were evolved during last three decades to understand the internal charge profile of polymer electrets. These methods essentially are based on the propagation of heat or pressure waves inside the charged samples. In both cases, electrical signals are generated due to mechanical or dielectric changes caused by heat diffusion or propagation of a pressure discontinuity in the sample. The charge distribution can be obtained from the electrical response. This paper presents detailed information on the thermal techniques to probe the charge distributions in the thickness direction of the polymer electrets as well as a comprehensive review of thermal data analysis. 相似文献
7.
真空腔测量空气折射率的方法及精度分析 总被引:1,自引:0,他引:1
空气折射率的测量及补偿效果在高精度激光干涉测量中起着“瓶颈”作用。分析了空气折射率的补偿原理 ,研究了用预抽气真空腔测量和补偿空气折射率的测量原理、方法及装置 ,分析了该方法对测量误差产生的原因。最后对测量精度作出了估计。 相似文献
8.
A.A. Hamza T.Z.N. Sokkar M.A. El-Morsy M.A.E. Nawareg 《Optics & Laser Technology》2008,40(8):1082-1090
A new method based on a mathematical model and a computer program is suggested to determine the refractive index profile of fibers having regular and/or irregular transverse sectional shape. Microinterferogram of both multiple-beam Fizeau fringes and the duplicated image from two-beam interference microscope are used for the determination of refractive index profile, cross-sectional area and shape of three different types of fibers. To confirm the suggested model, the calculated area and the shape of the transverse section of these fibers are compared with those results obtained using conventional methods. 相似文献
9.
Xiaohong Sun Hui Ma Hai Ming Zhiqiang Zheng Jiwen Yang Jianping Xie 《Optics & Laser Technology》2004,36(2):218-166
In this article, through the linear fit of objective distance and reciprocal of magnification in different imaging locations, we use imaging method to measure the central refractive index n(0) and focusing constant α of radial gradient index (GRIN) lens and obtain 10−3 measurement accuracy of n(0). At the same time, under distortion, the fourth-order refractive index coefficient and aberration of GRIN lens are derived. 相似文献
10.
Polymeric integrated-optical waveguides were prepared in a planar chip using UV-laser lithographic method. Five waveguide samples were irradiated by an excimer laser of wavelength 248 nm with different irradiation parameters (fluence and irradiation doses). Using Mach–Zehnder interferometer, the refractive index depth profiles of these samples are determined in two cases, directly and five years later of preparation. A crucial change of refractive indices profiles has been recorded after five years of preparation. In the first case we got double region waveguides fitted a Gaussian shape, while in the second one we observe a single region waveguide which has exponential shape. The photochemical reactions responsible for these changes in the two cases are demonstrated. This is quite important when such waveguides are used in the applications. Also it was interesting to investigate the aging impact on mode field distributions and the effective mode indices. The mode parameters are determined based on a theoretical model and the experimentally obtained data. The results show a notable change in the mode field distributions and the propagation coefficients as influence of aging. 相似文献
11.
Non-localized interference fringes, resulting from illuminating a film of PVA with a laser point source, have been used for measuring the refractive index of such a film. The refractive index of pure polyvinyl alcohol (PVA) film and five PVA films, doped with lead acetate of concentrations of 5, 10, 15, 20 and 25% by weight, have been investigated before and after irradiation by doses of 2, 4, 6, 8 and 10 Mrad gamma rays. It is found that, before irradiation, the refractive index increases with increasing the concentration of doped lead acetate. After irradiation the refractive index increases with increasing the dose up to a certain limit then decreases again. This indicates that the radiation deformation of gamma radiation is a chain scission effect. 相似文献
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提出并演示了一种基于单端探测的光纤传感器,可同时测量温度和折射率。微结构光纤探头由两个玻璃光纤微球拼接在一起,并在该探头的末端利用真空电子束蒸镀一层铝膜以增加反射,从而形成微球结构的马赫-曾德尔型光纤传感头。实验结果表明,该器件的温度灵敏度和折射率可分别达到50.77 pm/℃和-21.94 nm/RIU。这项工作提出了一种低成本、高分辨率的基于光纤方法实现的多功能传感应用。单端探测的马赫曾德尔型光纤传感器小尺寸的优势可应用到小体积气体的测量,而它的全二氧化硅设计提供了高温或化学严酷环境的兼容性。 相似文献
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Zhi-Cheng Jian 《Optics Communications》2006,268(1):23-26
Based on the total internal reflection of p-polarized light and the phase-shifting interferometry, an alternative method for measuring the two-dimensional refractive index distribution of a material is presented. The p-polarized light is incident on the boundary between a right-angle prism and a tested material. When the total internal reflection occurs at the boundary, and the p-polarized light has a phase variation. It depends on the refractive index of the tested material. Firstly, the two-dimensional phase variation distribution of the p-polarized light at the boundary is measured by the four-step phase shifting interferometric technique. Then, substituting the data into the special equations derived from Fresnel equations, the two-dimensional refractive index distribution of the tested material can be obtained. 相似文献