共查询到19条相似文献,搜索用时 140 毫秒
1.
体全息光栅线性记录折射率分布的修正 总被引:3,自引:1,他引:2
在讨论非线性记录体全息光栅的光谱特性时,发现一些文献在线性记录时折射率分布的表达式有些不妥.重新讨论了线性记录情况下折射率分布的表达式,引入了光束比和总光强折射率调制系数,用耦合波理论计算讨论了不同光束比和总光强折射率调制系数对光栅衍射光谱特性的影响.计算结果表明,光栅衍射光谱主峰峰值随总光强调制系数的减小而略有降低,主峰峰值随光束比减小下降得不大,带宽随总光强调制系数和光束比的减小而明显变窄,次峰峰值随总光强调制系数和光束比的减小而明显减小. 相似文献
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反射型体全息光栅对超短脉冲激光光束衍射的性质 总被引:2,自引:2,他引:0
在光栅记录介质色散效应的影响下,拓展Kogelnik的耦合波理论研究了反射型体全息光栅对偏振方向垂直和平行于入射面的超短脉冲激光光束衍射的性质。结果表明对于记录在LiNbO3光折变晶体中的体全息光栅,在色散效应、光栅参量和入射条件的共同影响下,光栅对偏振方向垂直于入射面的超短脉冲激光光束衍射的光谱带宽大于对偏振方向平行于入射面的超短脉冲激光光束衍射的光谱带宽,在不考虑光栅介质色散效应的影响时,它们都变大。进一步给出了衍射光的光谱带宽及光栅的衍射效率随入射脉冲的光谱带宽与光栅的光谱带宽比值的变化情况。 相似文献
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为研究局域体光栅的光折变形成机制及衍射特性,以双中心非挥发全息记录方案为基础,将带输运模型与二维耦合波理论相结合,采用数值模拟的方法.研究紫外敏化光强和记录红光总光强的变化对LiNbO3:Fe:Mn晶体中局域体光栅的影响,并给出定影结束时平均折射率调制、衍射光波振幅及衍射效率的模拟结果.研究发现:记录红光总光强不变时,平均折射率调制随紫外敏化光强增加而增加,而紫外敏化光强的改变对衍射波振幅的分布影响不大,衍射效率随紫外敏化光强度的增大先增大后减小,存在最佳紫外敏化光强,以获得80%以上的最高衍射效率.当紫外敏化光强不变时,随着记录红光总光强的增加,记录折射率光栅逐渐减弱,衍射波振幅分布变得越来越均匀.衍射效率逐渐降低. 相似文献
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超短脉冲激光光束在一维反射型体全息光栅中的衍射 总被引:6,自引:6,他引:0
基于Kogelnik的耦合波理论,研究了在色散效应的影响下,超短脉冲激光光束在反射型体全息光栅中衍射的性质.研究给出了衍射光及透射光在频谱域及时间域的振幅及强度分布、光栅的光谱宽度及衍射效率随光栅参量及入射条件的变化.数值研究的结果表明,在光栅记录介质色散效应的影响下,衍射光束的光谱宽度减小,脉冲展宽,衍射效率降低.通过适当的选取光栅参量及入射条件,可以控制衍射和透射光束的频谱和时间强度分布,得到满意的衍射和透射光束的带宽和波形,从而可以将其应用于脉冲整形等技术中. 相似文献
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高性能体全息光栅是全息波导的重要耦合元件,角带宽小、平均衍射效率不高是制约体全息光栅性能的重要因素。以不对称倾斜记录为出发点,设计并制备了大角带宽高衍射效率的体全息光栅。首先讨论在横电模式光和横磁模式光下体全息光栅的记录参数与其衍射效率的关系,找到平均衍射效率较高的记录参数范围,随后进一步分析在此范围内的记录参数与体全息光栅的角带宽的关系,从而确定获得大角带宽高衍射效率体全息光栅的最佳记录参数。实验结果表明:在参考光入射角度为25°、信号光入射角度为30°时,制备的体全息光栅的角带宽达到±14°,衍射效率为82%。 相似文献
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由一束球面波和一束平面波或者两束球面波干涉所形成的体全息光栅,由于其光栅矢量在全息图体积内是随位置的变化而变化的,所以被称为非周期型的体光栅。主要研究了用于体全息三维成像系统的非周期体光栅的深度选择特性。根据叠加的原理,将非周期体光栅看作多个固定周期的基元体光栅的叠加,结合耦合波理论分析非周期体光栅的衍射特性。采用这一方法,利用Matlab软件模拟,研究了两束记录光夹角对所记录的非周期体光栅深度选择性的影响和在两束记录光夹角相同时,球面参考光体全息成像系统及平面参考光体全息成像系统深度选择性的差别,最后在光折变晶体材料中进行非周期型和周期型体光栅的记录和再现,对模拟结果进行了实验验证。 相似文献
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Contribution of Absorptive and Refractive Gratings to Mixed Holograms Using Xanthene-Dye-Doped Films
The contribution of absorptive and refractive gratings to a mixed hologram is investigated by means of two-wave coupling technique by moving a hologram. Polyvinyl alcohol films doped with xanthene-dyes such as erythrosin B,eosin Y, uranin and fluorescein which absorb an argon-ion laser light of 488 nm and 515 nm are used as hologram recording materials in our experiment. A simple model of the two-level one-step photo-bleaching well explains the growth of an absorptive grating and the refractive index and also the working wavelength dependence of growth of the refractive grating in the xanthene-dye-doped films. 相似文献
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Self-talkofReflectionHologramDuringitsconstruction¥LIUDahe;ZHOUJing(DepartmentofPhysics,BeijingNormalUniversity,Beijing100875... 相似文献
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LI DeNow is working in the Institute of Military Police LIU Dahe 《Chinese Journal of Lasers》1999,8(4):348-354
ntroduction SimpleandorrigorouscoupledwavetheoriesbasedonthephysicalmodelofBraggdiffractionwereusedgenerallyintheanalysisofvolumehologram[1~4]-However,theactualdistributionofrefractiveindexinavolumehologramiscontinuousandthestructureofhologrammediu… 相似文献
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The spectral characteristics of volume hologram is analyzed using Fresnel coefficient matrix. The volume hologram is treated as a medium in which the refractive index changes continuously. The analysis is in good consistency with previous experimental results of volume hologram. 相似文献
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用特征矩阵法研究一维激光全息光子晶体的禁带特性 总被引:2,自引:1,他引:1
介质中传播方向相反的2束激光干涉可形成具有一维周期结构的体积全息图,而这种全息图可以看作一维光子晶体,称为一维激光全息图光子晶体,用特征矩阵法研究了一维激光全息图光子晶体的透射谱中的禁带随入射角、记录波长、介质折射率、折射率调制度的变化规律。结果表明:当入射角变大,激光波长、介质折射率及介质折射率调制度变小时, 禁带的位置向短波方向移动, 禁带宽度减小。 相似文献
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P. F. Romanenko N. V. Sopinskii I. Z. Indutnyi E. F. Venger G. B. Beketov 《Journal of Applied Spectroscopy》1999,66(4):664-668
We devised a method of producing blaze hologram diffraction gratings by transforming symmetric grooves of the original grating
into asymmetric ones using an additional oblique irradiation by monochromatic or polychromatic light and a repeated chemical
etching of the additionally irradiated grating. Photosensitive As2Se3 film layers are used as a photoconductive material for recording gratings. A numerical computer modeling of the formation
of asymmetric grooves is conducted. The calculated shape of the groove profile is in good agreement with experimental data.
The manifestation of asymmetry of the profile shape of the produced gratings in angular and spectral relations for their diffraction
efficiency is considered. It is shown that by varying the parameters of producing the original gratings and the conditions
of their additional treatment it is possible to obtain hologram gratings with the required profile shape and blaze angle.
To whom correspondence should be addressed.
Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 45, Nauka Ave., Kiev, 252028, Ukraine. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 587–590, July–August, 1999. 相似文献
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Numerical simulation of the optical properties of unslanted reflection holographic gratings (holographic mirrors) is made by the characteristic matrix method. The holograms are recorded in an attenuating medium but the reconstruction is that of pure phase structures in which the refractive index depends exponentially on the exposure. The dependence of the hologram spectral selectivity on medium absorption, amplitude ratio of the two interference waves and recording linearity is studied. 相似文献
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Ding Wang 《Optics Communications》2006,267(1):79-82
A true color stereoscopic hologram is made with one-wavelength laser. Under illuminating incandescent lamp, a true color stereoscopic image can be seen from the hologram. A diffused reference light and a project object light are used in the recording of the hologram. The three primary color images of natural scenery are encoded on a white-and-black film. With the help of the encoded film, a true color hologram is recorded on a plate by single exposure and a true color stereoscopic by two exposures. The simplification of this method is apparent. Further more, it largely decreases the scattering noise of the hologram and averts the problem of color lack fidelity of the holographic image. 相似文献
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Daisuke Sakai Kenji Harada Shun-ichi Kamemaru Daisuke Barada Fuminobu Sato Takashi Fukuda 《Optical Review》2009,16(3):335-338
We propose a method of hologram recording in a glass plate by corona charging. The holographic recording materials used in
this study are conventional soda-lime glass and azobenzene polymer film. A Fourier transform hologram on an azobenzene polymer
film coated on the glass plate is recorded in the glass plate by corona charging. After removing the polymer film, the hologram
recorded in the plate can be reconstructed using a visible-wavelength laser beam. The first-order diffraction efficiency of
the hologram at a wavelength of 532 nm is 0.03%; the efficiency depends on the depth of the surface relief structure on the
azobenzene polymer film and the corona-charging time. The hologram recorded in the glass plate has high environmental resistance. 相似文献