共查询到20条相似文献,搜索用时 62 毫秒
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空间相干性问题来源于扩展光源不同部分发光的独立性,表现在波场横向相干范围;时间相干性来源于光源发光过程在时间上的断续性,表现在波场的纵向相干范围. 本文从干涉条纹的可见度出发,对双棱镜干涉实验中的相干性问题进行分析讨论,推导出相干长度和临界宽度公式,给出双棱镜干涉实验测量光波临界宽度和相干长度,以及估测滤光片单色性的实验方法. 相似文献
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扼要说明了空间相干的意义及干涉条纹反衬度的表达式,介绍了一种多数物理实验室可实现的可空间相干性定性观察和定量测量的方法。 相似文献
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通过我们设计的实验装置,能将通常双缝干涉实验中的d值从1mm加宽到5mm,论证了bβ〈λ判据,验证了光场的空间相干性,并通过实验论证了“看不到”不等干涉条纹不存在。本实验通过衍射光栅的知识和实验现象,可以间接“看到”干涉条纹的存在。它能帮助学生理解光场的空间相干性,对教学有很好的启发作用。 相似文献
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随着高性能第三代同步辐射光源的建成开放,基于X射线相干特性的实验方法得到了快速发展和广泛应用.作为一个典型的例子,X射线相位衬度成像已经成为常规的X射线实验方法并向用户开放.相干散射、相干衍射成像、光子关联谱等X射线实验方法正日益受到重视,在高空间分辨、时间分辨等研究领域已显示出其独特的优越性.因此,研究和测量第三代同步辐射的空间相干特性对进一步发展这些新的实验方法具有重要意义.基于Talbot自成像原理成功测量了上海光源X射线成像线站发射的X射线的空间相干长度,并进而测得了相应光源的空间尺度.光子能量为33.2 keV时,测得的X射线光束垂直方向空间相干长度为8.84μm,对应的光源尺寸为23μm,测量结果与理论分析相符. 相似文献
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Investigation on spectral-domain optical coherence tomography using a tungsten halogen lamp as light source 总被引:1,自引:0,他引:1
The objective of this research was to investigate a new detection method using a thermal light source in a spectral domain
optical coherence tomography (SDOCT) operation to improve both image acquisition rate and axial resolution economically. A
tungsten halogen lamp was chosen as the illumination source and a Michelson fiber interferometer was employed to generate
the interference pattern of an object collected by a spectrometer; the inner structure of the object was obtained from the
interference pattern by a Fourier transform. An experiment was performed by measuring a thin film coated on a glass base with
the system, and the experimental results indicated that the structure of the thin film could be clearly observed as expected.
It was theoretically stated and experimentally verified that the technique was feasible and enables imaging to realize the
reconstructions of internal structure of engineering and biological object. 相似文献
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本文首次提出一种由相干度非线性调制得到的新型光学双稳态——空间双稳态及其作用无耦合和有交叉耦合情况下,经γ/υ和υ/ν变换反馈可得到多种形式的双稳态,且给出了几种情况下的稳态特性方程、参数选择区域以及翻转条件等. 相似文献
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报道了一种新型的专用于光学相干层析系统的输出光谱为准高斯型的宽带超荧光光纤光源.该光源采用掺饵光纤作为增益介质.其关键技术是在抽运源的输出端增加了光耦合器,并在光源输出端插入多级长周期光纤光栅对铒离子的自发光谱进行调制和整形;同时采用光控器和温控器来控制抽运源的输出以提高光源输出功率的稳定性.该光源的中心波长为1.57μm,输出光谱的3dB带宽大于75nm,输出功率为27mW.实验结果表明,该光源输出光谱的自相关函数的旁瓣峰被大大削弱,可以满足光学相干层析系统的应用.
关键词:
光学相干层析术
超荧光光纤光源
长周期光纤光栅
光耦合器 相似文献
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对用空间扩展宽谱光源再现的彩虹全息像的分析 总被引:1,自引:2,他引:1
用空间扩展宽谱光源再现的彩虹全息像时,整个光源只在一定的光谱的和空间的“有效宽度”内起作用,本文在此概念的基础上,研究了光源的光谱扩展和空间扩展在其单独作用和联合作用时对全息像的影响。发现当两者联合作用时,对像质的总影响几乎与它们单独作用时一样。给出了用宽谱空间扩展光源所再现的彩虹全息像的分辨率,从而提出了一个实用的狭缝宽度。 相似文献
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A simple method to measure the complex degree of spatial coherence of a partially coherent quasi-monochromatic light field is presented. The Fourier spectrum of the far-field interferogram generated by a mask with multiple apertures (small circular holes) is analyzed in terms of classes of aperture pairs. A class of aperture pairs is defined as the set of aperture pairs with the same separation vector. The height of the peaks in the magnitude spectrum determines the modulus of the complex degree of spatial coherence and the corresponding value in the phase spectrum determines the phase of the complex degree of spatial coherence. The method is illustrated with experimental results. 相似文献
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Rafael Betancur John Restrepo Roman Castaneda 《Optics and Lasers in Engineering》2009,47(12):1340-1347
A novel technique for designing specific shapes of power distributions is presented. It bases on the modulation of the spatial coherence of the optical field in amplitude and phase. The modulating functions are synthesized from the phase-space diagram of the field, provided by the marginal power spectrum. Numerical results for the phase modulation of the complex degree of spatial coherence are presented. This beam shaping technique is suitable in applications that require specific shapes and sizes. 相似文献