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白光横向平顶光束在定向背光式自由立体显示器中有重要应用.本文提出一种采用带蝶形小孔阵列的衍射掩模片获得白光横向平顶光束的方法.根据广义惠更斯-菲涅耳衍射积分和多波长叠加原理,推导出光强分布计算式.设计一套实验装置,数值模拟并实验验证出射光束在不同距离的横向光强分布以及小孔蝶形凹度(蝶形中心高度与边长的比值)对横向光强分布的影响.结果表明:当选择小孔蝶形凹度为0.50—0.66时,可以得到平顶因子F 0.89的白光横向平顶光束,横向平顶光束的宽度随着传输距离的增大而增大,而平顶因子基本不变.实验还发现柱面透镜的折射色散和衍射色散可以互相抵消,使白光横向平顶光束基本无色散. 相似文献
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Propagation properties of partially coherent Laguerre-Gaussian beams in turbulent atmosphere 总被引:2,自引:0,他引:2
Yanli Zhong 《Optics & Laser Technology》2011,43(4):741-747
To study the propagation properties of partially coherent Laguerre-Gaussian (PLG) beams through turbulent atmosphere, the analytical formulas are derived for the angular width and the beam-propagation factor (M2-factor) of PLG beams by using the extended Huygens-Fresnel principle and the second-order moments of the Wigner distribution function (WDF). The corresponding numerical results are also calculated. When propagation distance increases, the angular width is found to spread faster for PLG beams with higher beam order, smaller correlation length and bigger structure constant The angular width of PLG beams decreases with increase in waist width (w0).The M2-factor of PLG beams with higher beam order and smaller correlation length is less affected by turbulence with increase in propagation distance. The propagation properties of the M2-factor for PLG beams with the smaller structure constant are better than that with bigger structure constant . The M2-factor of PLG beams decreases with increase in the wavelength λ, and it is also less affected by turbulence for beams with higher order and smaller correlation length. Furthermore, for the PLG beams with the same beam order, the angular width and the M2-factor keep invariable in free space. 相似文献
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研究了部分相干高斯谢尔光束在大气湍流中的到达角起伏.主要采用湍流内外尺度的修正Von Karmon谱模型及广义惠更斯-菲涅尔原理和交叉谱密度函数推导出了部分相干光在大气湍流中的到达角起伏表达式.对比分析了湍流内外尺度、湍流强度、传输距离、源相干参数以及波长等参数对部分相干光在大气湍流水平路径上传输时的到达角起伏的影响.结果表明:随着传输距离的增加,到达角起伏越来越小;随着大气湍流内外尺度和源相干参数的增加,到达角起伏也越来越大;与部分相干光相比,完全相干光的到达角起伏受湍流影响很小;随着波长和湍流强度的减小,到达角起伏越来越小. 相似文献
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By means of the extended Huygens-Fresnel integral formula in the paraxial approximation and based on the fact that a hard aperture function can be expanded into a finite sum of complex Gaussian functions, an approximate analytical expression for Bessel-Gauss beams propagating in a turbulent atmosphere truncated by an aperture has been derived. The result is more convenient for studying the axial intensity distribution properties of Bessel-Gauss beams with different topological charges in a turbulent atmosphere than the usual way by using diffraction integral directly. Utilizing the analytical expression, the axial intensity distribution of such kind of beam in a turbulent atmosphere is investigated numerically in detail. Results show that the intensity distribution on the axis changes with the variation of the beam topological charge m, the wavelength and beam waist width of the initial beam and the turbulent strength. 相似文献
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Takashi Tsuchitani Sumio Nakahara Hisaharu Tottori Kazuhito Kanazawa Takeyoshi Fujita 《Optical Review》2008,15(1):44-50
We propose and demonstrate a method which constructs large size multicolor images using a holographic technique in limited
spaces, i.e., tunnels. A traffic sign image of the same size and color as an actual traffic sign board is displayed using
many comparative small holograms. Each hologram is composed of a single computer generated hologram (CGH). Though it was necessary
to make many CGHs, we have shortened the hologram production time by putting a reconstructed image on long distance, and using
many reconstruction sources. Moreover, though cross-talk images are caused in a color reconstruction, by adjusting the optical
system it is possible to make sure that drivers see only the appropriate image. Many holograms function as one big hologram,
and it has been confirmed that a large reconstructed image can be displayed in a limited space. 相似文献