共查询到17条相似文献,搜索用时 125 毫秒
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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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从部分相干光的传输理论出发,研究了高斯-谢尔模型光束通过光阑像散透镜聚焦的光谱异变和光谱开关。研究表明,在考虑像散的情况下,聚焦场轴上也会出现光谱异变和光谱开关。光谱异变和光谱开关不仅与空间相关性、截断参量、菲涅耳数和源光谱谱宽有关,透镜像散对光谱异变和光谱开关也会产生影响。通过数值计算结果,重点对透镜像散对光谱移动和光谱开关的影响进行了分析。与无像散情况相比,像散会使出现光谱开关的临界位置发生变化,当像散较大时出现光谱开关的临界位置明显向几何焦面移动,特别是当像散增加到一定数值时,光谱开关会消失。 相似文献
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杨氏实验远场的光谱位移和光谱开关 总被引:9,自引:4,他引:5
从部分相干光的传输定律出发,研究了杨氏双缝实验远场的光谱变化。指出杨氏实验中光谱开关在远场也会出现.缝的衍射和光的空间相干性是产生光谱开关的物理原因,增大缝参量ε和源的空间相关度△光谱开关效应越显著。作了详细的数值计算以说明远场光谱位移和光谱开关的特性,并与已有的工作进行了比较。 相似文献
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基于广义惠更斯-菲涅尔原理,推导出了超短脉冲厄米-高斯(H-G)光束在湍流大气中的光谱传输方程,研究了其光谱移动和光谱跃变特性,并给予了合理的物理解释.研究表明,超短脉冲H-G 光束通过湍流大气传输其光谱特性由大气折射率结构常数、厄米多项式阶数、脉冲宽度和观察点位置坐标等因素共同决定.轴上点光谱为蓝移,随着离轴距离的增大,光谱由蓝移变为红移,无光谱移动点的位置坐标与脉冲宽度无关.此外,当湍流增强到一定程度时离轴点还存在光谱跃变现象.自由空间与湍流大气中的光谱跃变行为存在很大的差异,本文对此进行了详细的分析.
关键词:
超短脉冲厄米-高斯(H-G)光束
湍流大气
光谱移动
光谱跃变 相似文献
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部分相干光被色差透镜聚焦的光谱异常现象 总被引:10,自引:10,他引:0
研究了色差透镜聚焦宽频带部分相干光,观察到在聚焦光场轴上点出现的光谱奇异现象.结果表明:与入射光的光谱比较,聚焦光场某些轴上点的光谱发生很大的变化.这种光谱变化不仅与透镜的色差有关,而且还与入射的部分相干光的相干度有关.当色差一定时,部分相干光空间相干度越大,色差对轴上点光谱的影响就越大.而当部分相干光空间相干度一定时,色差越大,轴上点光谱的变化也就越大.研究结果还表明,在一定的条件下,光谱位移会发生快速变化,即发生了光谱开关现象. 相似文献
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In this paper, the effects of chromatic aberration of a focusing lens on the normalized spectrum of the partially coherent light at the geometrical-image plane are investigated experimentally. The experimental results show that, compared to the source spectrum, the normalized spectrum of the partially coherent light at the geometrical-image plane shifts either towards the red side or towards the blue side, which is dependent on the position of the observation point. In particular, the normalized spectrum splits into two peaks at some points and the spectral switch occurs at the critical point. Furthermore, each of the two peaks of the normalized spectrum still split into two subpeaks respectively at some points and the spectral switch occurred in the short-wavelength range of the normalized spectrum is also observed at another critical point. 相似文献
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The spectral behavior of polychromatic spatially fully coherent Gaussian beams diffracted at an aperture in the far field is studied based on the propagation law of the cross-spectral density function. Detailed numerical calculation results are presented, and illustrated. It is shown that the spectral changes take place in the vicinity of zeros of the Airy pattern, and the spectral modifier depends on the truncation parameter δ and diffraction angle α. The critical diffraction angle αc, at which the spectrum is split into two lines with equal height i.e., the spectral switch appears, varies with truncation parameter δ. The spectral switch vanishes if δ becomes large enough. A detailed comparison with the previous publications is given, showing somewhat extension made in our work. 相似文献
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随着光谱成像技术的发展,以高空间分辨率和高光谱分辨率获得的图像极大地提高了地物目标的识别能力,为准确获取地物被测目标的二维空间影像信息和一维光谱信息,设计完成一种基于声光可调滤波器(AOTF)的高光谱成像系统,但由于系统中偏振片消光比有限,导致视场外的0级光与被测目标的+1级衍射光发生重叠,而AOTF无驱动时成像可近似为0级干扰的图像,为此提出一种AOTF加驱动图像减无驱动图像的0级干扰抑制方法。并采用该系统样机进行外场光谱成像实验,对结果进行0级干扰抑制方法修正,修正后的结果表明该方法不仅大幅度消除了0级光的干扰,而且还提高了整个成像光谱的测量精度。 相似文献
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Starting from the Rayleigh-Sommerfeld diffraction integral and without invoking the paraxial approximation, analytical expressions for the field distribution, far-field power spectrum and temporal far-field distribution of chirped Gaussian pulses diffracted at a circular aperture are derived, which enables us to study the spectral anomalous behavior of diffracted chirped Gaussian pulses in the far field. The potential applications of spectral anomalies of ultrashort pulses are discussed. It is found that at the critical angle the spectral switch appears. The frequency difference between the two equal heights of spectral switches increases and the corresponding critical diffraction angle slightly increases as the chirp parameter increases and pulse duration decreases. In a certain region of the truncation parameter, the critical angle decreases with increasing truncation parameter. By suitably varying the pulse duration, chirp parameter and truncation parameter, information encoding and transmission are achievable in the use of chirped Gaussian pulses. 相似文献
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Slightly dispersive white-light spectral interferometry to measure distances and displacements 总被引:1,自引:0,他引:1
A new spectral-domain interferometric technique of measuring distances and displacements is realized when the effect of low dispersion in a Michelson interferometer, which comprises two coated plates of a beam splitter and a compensator, is known and the spectral interference fringes are resolved over a wide wavelength range. First, processing the recorded spectral interferograms by an adequate method, the unmodulated spectrum, the spectral fringe visibility function and the unwrapped phase function are obtained. Then, knowing the dispersion relation for the fused-silica plates, the ambiguity of the unwrapped phase function is removed and the thickness of fused silica and the nonlinear phase function due to the effect of the coatings are determined by using a new procedure. It is based on the linear dependence of the overall optical path difference between interferometer beams on the refractive index of fused silica. Once the thickness and the nonlinear phase function are known, the positions of the interferometer mirror are determined precisely by a least-squares fitting of the theoretical spectral interferograms to the recorded ones. 相似文献
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Based on the extended Huygens-Fresnel principle, the spectrum of elliptical Gaussian beam (EGB) propagating through turbulent atmosphere can be derived analytically by tensor method. It can avoid time-consuming numerical integral that was commonly used in the previous study of spectral changes. Analytical results show that the on-axis normalized spectrum S(ω) of EGB propagating through turbulent atmosphere is different from the original spectrum S0(ω) and there exist spectral shifts and spectral switches for EGB propagating through turbulent atmosphere. Besides, spectral shifts and spectral switches of EGB are closely related with the structure constant of the turbulent atmosphere, the beam parameters and the coordinate of observation point. Compared with the Gaussian beam, there are two spectral switches for EGB propagating through turbulent atmosphere. 相似文献