排序方式: 共有109条查询结果,搜索用时 0 毫秒
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柱面球差透镜聚焦部分相干光束的焦移 总被引:1,自引:1,他引:0
通过定义聚焦光束的等效菲涅耳数,研究了部分相干光经柱面球差透镜聚焦后的轴上光强分布,得到了相对焦移的简单公式,即相对焦移反比于等效菲涅耳数的平方.结果表明,这种基于等效菲涅耳数的计算聚焦光学系统的焦移方法是计算部分相干光束经球差透镜聚焦相对焦移简单且有效方法.还讨论了一种特殊等效菲涅耳数为纯虚数情况.结果证明,在这种情况下,该相对焦移简单公式仍然有效. 相似文献
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The spectral changes of a partially coherent polychromatic light focused by an apertured lens with chromatic aberration are investigated. It is demonstrated that the spectrum in the focused field is different from that in the aperture. Comparing with the spectrum in the aperture, the spectrum in the focused field shifts to lower or higher frequency, which is defined as a spectral shift. The influence of chromatic aberration of the lens, the coherence of the partially coherent light in the aperture, the radius of the aperture, and the spectral width of the spectrum of the aperture on the spectral shift are investigated in detail. The numerical results show that these parameters affect the spectral shift noticeably. 相似文献
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杨氏双缝干涉实验中光谱奇异现象的特性分析 总被引:1,自引:1,他引:1
研究了完全相干光和部分相干光分别照射双缝时,杨氏双缝干涉实验中干涉场区的光谱变化现象.根据干涉场中光谱标准矩定义了光谱的相对光谱移动和相对光谱增宽,并利用相对光谱位移和相对光谱增宽分析了光谱奇异现象的特性.研究结果表明,入射光的某些光谱参量(如源光谱宽度Γ0,中心拦截比ε,相对空间相干度Δ0)对相对光谱增宽的影响相当大.结果还表明了光谱标准矩方法是定量研究光在传输中的光谱变化以及光谱奇异现象的有效工具. 相似文献
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This paper studies the tight focusing properties of femtosecond elliptically polarised vortex light pulses. Based on Richards--Wolf vectorial diffraction integral, the expressions for the electric field, the velocity of the femtosecond light pulse and the total angular momentum of focused pluses are derived. The numerical calculations are also given to illustrate the intensity distribution, phase contour, the group velocity variation and the total angular momentum near the focus. It finds that near the focus the femtosecond elliptically polarised vortex light pulse can travel at various group speeds, that is, slower or faster than light speed in vacuum, depending on the numerical aperture of the focusing objective system. Moreover, it also studies the influence of the numerical aperture of the focusing objective and the time duration of the elliptically polarised vortex light pulse on the total angular momentum distribution in the focused field. 相似文献
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大功率单色LED的空间相干特性 总被引:1,自引:0,他引:1
基于van Cittert-Zernike定理,从理论上计算出大功率单色发光二极管(LED)辐出光,在空间中传输后的空间相干性分布。计算结果表明,自发辐射的LED光源其辐射光在空间中传输后,由非相干光变为部分相干光,且其空间相干性与LED芯片的结构有关。实验上采用双缝干涉对LED辐射光的空间相干性进行测量,由干涉条纹的可见度与两点间的相干度之间的关系得出,非相干LED光源的辐射光在传输后为部分相干光。而采用间隔可调的双缝干涉测量两点间的相干度后发现,LED的芯片发光区域决定了其辐射光在传输中的空间相干性分布。理论计算的空间相干性分布与实验测量结果基本吻合。 相似文献
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Propagation properties of stochastic electromagnetic double-vortex beams in turbulent atmosphere 下载免费PDF全文
Based on the extended Huygens-Fresnel principle, we study the propagation properties of stochastic electromagnetic double-vortex beams in turbulent atmosphere. The result shows that the spreading of the partially coherent double-vortex beams can be smaller than that of the fully coherent ones. The degree of polarization of this kind of beam will experience change, which is dependent on the degree of polarization of the source plane, the atmospheric turbulence, topological charge, and the spatial coherence. The results may have applications in space optical communication. 相似文献
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Spiral spectra of vortex beams with coma aberration are studied. It is shown that the orbital angular momentum (OAM) states of vortex beams with coma aberration are different from those aberration-free vortex beams. Spiral spectra of beams with coma aberration are spreading. It is found that in the presence of coma aberration, the vortex beams contain not only the original OAM component but also other components. A larger coma aberration coefficient and/or a larger beam waist will lead to a wider spreading of the spiral spectrum. The results may have potential applications in information encoding and transmittance. 相似文献
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