共查询到18条相似文献,搜索用时 276 毫秒
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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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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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推导出多色高斯光束和高斯-谢尔模型光束通过杨氏实验双缝传输的谱强度公式.对完全空间相干光和部分空间相干光照明杨氏实验装置出现的光谱开关作了详细研究,并判断其是否属于奇点光学效应. 结果表明:多色场奇点光学效应的判据应当是光谱开关出现时的谱强度极小值Smin=0,而不是总光强极小值Imin=0. 当用多色高斯-谢尔模型光束照明杨氏实验装置时,在近场和远场产生的光谱开关都不属于奇点光学效应. 当用多色高斯光束照明杨氏实验装置时,只有远场产
关键词:
光谱开关
奇点光学效应
完全相干和部分相干
多色光场 相似文献
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Carlos J. Zapata-Rodríguez 《Optics Communications》2006,257(1):9-15
The power spectrum of polychromatic apertured spherical waves changes strongly in the vicinity of phase singularities. A spectral shift effect is observed and, in some cases, a spectral switch occurs together with a broadening of the power spectrum. Low-order moments of the power spectrum are evaluated in points of the focal volume with spectral anomalies. First-order analytical expressions are proposed for the evaluation of the relative spectral shift and the relative spectral broadening in the transverse focal plane and along the optical axis. The influence of the fractional bandwidth and the selected singularity order is considered. 相似文献
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Lü Baida & PAN Liuzhan . Institute of Laser Physics Chemistry Sichuan University Chengdu China . Department of Physics Luoyang Normal College Luoyang China . State Key Laboratory of Laser Technology Huazhong University of Science Technology Wuhan China Correspondence should be addressed to L Baida 《中国科学G辑(英文版)》2004,47(1):24-35
Inrecentyearsanewbranchofmodernphysicalopticscalledsingularoptics[1]hasbeendeveloped.In2002theworkinsingularopticswasextendedfrommonochromaticlighttospatiallyfullycoherentandpolychromaticlightbyGburetal.[2—4].Itwasfoundthat,whenaconverging,spatiallyfullycoherentandpolychromaticsphericalwaveisdiffractedatanaperture,anomalousspectralchangestakeplaceclosetozerosoftheintensityinthefarfield;i.e.thespectrumisredshiftedatsomepoints,blueshiftedatothers,andsplitintotwolineselsewhere.Thepredictionsofsp… 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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Carlos J. Zapata-Rodríguez 《Optics Communications》2006,263(2):131-134
The diffraction-induced spectral anomalies in the focal plane of an apertured spherical wave with supercontinuum flat-top power spectrum are investigated. Coherent broadband radiation (also incoherent white light) demonstrates a strong blue shift in the vicinity of the optical axis, and discrete spectral gaps with overall red shift arise out of this central region. Unlike narrow-band light, the spectral switch effect fades away with ultra-broad spectra. 相似文献
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The influence of nonparaxiality on the spectral behavior in Young's experiment illuminated by partially coherent light 下载免费PDF全文
Starting from the Rayleigh--Sommerfeld diffraction integral, this
paper studies the spectral behavior in Young's experiment
illuminated by nonparaxial partially coherent light and compares
with the paraxial case, where the influence of nonparaxiality of
partially coherent light on the spectral shifts and spectral
switches is stressed. It is shown that there is a spectral shift in
the nonparaxial case relative to the paraxial one and the critical
position changes, at which the spectral switch occurs. The ratio of
the waist width to the central wavelength w0/λ0 and
relative spatial correlation length \De affect the spectral
difference. The smaller w0/λ0 is, the larger the
difference between the nonparaxial and paraxial results appears. The
effect of relative spatial correlation length Δ is relatively
small. 相似文献
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It has been shown both theoretically and experimentally that drastic spectral changes take place around phase singularity and the shift in the spectral lines gives rise to the phenomenon called spectral switching. The shift of spectral lines towards the blue end or towards the red end of the spectrum might perhaps be used in free space communication applications. In more recent investigations, the possibility of information encoding with spectral anomalies have been discussed for two different optical systems. In this paper, we present schemes of information encoding and information hiding in the Airy pattern formed by diffraction of spatially coherent light after passing through a circular aperture. We propose a communication system that might be used to realize a new communication technique. 相似文献
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根据Li提出的平顶光束模型和部分相干光理论,推导出部分相干平顶光束在线性增益(损耗)介质中传输的光谱分布解析表达式,定量研究了部分相干平顶光束在线性增益(损耗)介质中传输的光谱特性,分析了近场和远场轴上光谱的变化特点,以及介质的增益(损耗)特性、光源的中心频率、空间相干参数以及谱宽等因素对光谱变化的影响. 研究结果表明,部分相干平顶光束在线性增益(损耗)介质中传输时,光源的中心频率、光谱宽度、空间相干参数对相对谱移量影响较大,但对光谱分布随传输距离的总体变化趋势影响较小,而光谱分布随传输距离的总体变化趋势则主要由平顶光束的阶数所决定.
关键词:
部分相干平顶光束
光谱特性
谱移
线性增益(损耗)介质 相似文献
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R.A. van Calcar M.J.G. Heuts B.K. van Uitert H.A.J. Meijer Tj. Hollander C.Th. Alkemade 《Journal of Quantitative Spectroscopy & Radiative Transfer》1981,26(6):495-502
Prior to power broadening experiments on the Na-D lines in a flame (described in Part II), we investigated the time-dependent spectral and spatial properties of a flashlamp-pumped pulsed dye laser (pulse duration about 800 ns, FWHM), with Rhodamine-6G in methanol as dye liquid and an interference filter combined with a Fabry-Pérot etalon as bandwidth-restricting elements in the cavity. An experimental set-up is described that permits measurements of time-dependent spectra with a time-resolution of 10 ns and a spectral resolution of 2.5 × 105. Results are given for different concentrations of the dye solution and for two different bandwidth settings of the laser. In general the spectral profiles at different moments during the pulse are well described by Gaussian curves. The spatial profiles at different moments during the pulse are best fitted by Lorentzian curves. At small concentrations of the dye solution, the time behaviour of the shift and the bandwidth are in (qualitative) agreement with theoretical predictions, i.e. a narrowing of the bandwidth and a shift to longer wavelengths of the line centre. 相似文献