共查询到20条相似文献,搜索用时 0 毫秒
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M. R. Tubbs 《Optics & Laser Technology》1973,5(4):155-161
The organization of a random access read-write-erase holographic optical memory is described, and estimates are given for the characteristics required of a reversible holographic storage material suitable for this application. The characteristics of photo-chromic, thermo-chromic, and electrically controlled materials are surveyed to indicate how far existing materials satisfy, or could be developed to satisfy, the requirements of fast optical information storage. A figure of merit is defined to indicate the relative value of existing materials for storage applications. 相似文献
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T. B. Dávila 《Optics and Spectroscopy》2007,103(6):862-867
A multicomponent lattice Boltzmann model including external electric forces interactions is developed to study the behavior
of a classical thermoplastic film which is used as a holographic recording material. The model incorporate also the spinodal
decomposition originated in this type of polymeric fluids when a fast thermal pulse is used to develop the hologram. The surface
deformation of the electrically charged thermoplastic film is simulated using the lattice Boltzmann model and the main holographic
parameters, i.e., spatial frequency response (MTF) and diffraction efficiency are given and related to the hydrodynamic behavior
of the fluid. The influence of the phase transition on the growth rate of the deformation and, hence, on the MTF response
of the medium is studied and correlated with experimental results. The results obtained with our model are in agreement with
those obtained using more complex theoretical analysis.
The text was submitted by the author in English. 相似文献
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P. Cheben M. L. Calvo F. del Monte O. Martínez-Matos J. A. Rodrigo 《Optics and Spectroscopy》2007,103(6):855-857
The advances in the sol-gel holographic recording materials, namely in the photopolymerizable compositions and photorefractive
glasses, are reviewed. A new sol-gel holographic material is also discussed that exploits diffusion of a high-refractive-index
MA:Zr complex, with the refractive index modulation of n ∼ 10−2 and negligible scattering.
The text was submitted by the authors in English. 相似文献
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Photopolymer holographic recording material 总被引:1,自引:0,他引:1
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Volume holograms are stored in KCl:Na crystals using the photoinduced reorientation of FA centers. The dependence of the diffraction efficiency on the directions of polarization of the recording and the reconstructing waves are shown. Experimental results are in good agreement with the calculated curves, predicted by the theory. 相似文献
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To fully support phased-array antenna and other applications, a 3-range (long time, moderate time, and short time) delay line structures with holographic optical elements is proposed. Flexibility, light-weight, on-axis coupling, easy alignment, easy fabrication, and compactness are their advantages. When use holographic optical elements to build the photonic delay line system, all of the delay and non-delay paths in these three photonic delay lines are setting in a compact structure. They do not need any extra components, such as mirrors and optical paths in free space, and can bear stronger vibration. Therefore, the holographic optical elements are more suitable to design the photonic delay lines. In these three structures, their losses and crosstalk s are balanced. All of delay and non-delay cases in these three delay line structures, their crosstalk, signal-to-noise ratio, and loss are 1/81,000, 59.1 dB, and 3.2 dB, respectively. Finally, to support complete applications, a polarization independent photonic delay line system with holographic optical elements is proposed, too. 相似文献
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一种间接测量相位型全息记录介质折射率调制度的方法 总被引:1,自引:0,他引:1
为恰当评价各种相位型全息记录介质的衍射能力及相应的各种处理工艺,本文给出一种利用分光光度计测量介质折射率调制度的原理和方法. 相似文献
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P. Markovsky 《Optical and Quantum Electronics》1996,28(2):147-154
The influence of the matrix type-aqueous suspensions, polyacrylamide gel and gelatin — on the photoinduced changes in bacteriorhodopsin-containing samples is investigated experimentally. The influence of the readout light on the diffraction efficiency behaviour and the photoinduced anisotropy is shown. The change in the refractive index in directions parallel and perpendicular to that of the exciting light polarization as a function of the intensity has been measured. The theoretical photoprocess taking place with bacteriorhodopsin molecules is investigated on the basis of a macroscopic model. 相似文献
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An experimental study of variation of sensitivity with recording and sensitizing intensities in two-center recording is presented. The experimental results are in good agreement with the theoretical predictions. It is shown experimentally, for what is to our knowledge the first time, that the sensitivity is a function of the ratio of recording to sensitizing intensities and not the absolute intensities. Also, the ratio of recording to sensitizing intensities should be small to obtain high sensitivity values. We also report the highest sensitivity (S=0.15 cm/J) that has been achieved to date for a LiNbO3:Fe:Mn crystal. 相似文献
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Sensitivity improvement in two-center holographic recording 总被引:9,自引:0,他引:9
Persistent holograms are recorded with green light in LiNbO(3) crystals doped with Mn and Fe. The recording sensitivity is 20 times better than that obtained by recording with red light. Partial loss of persistence is caused by using green light for recording. 相似文献
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Photo-induced processes in organic materials mostly occur on molecular levels. Excited molecules may split to form radicals, starting a polymerization process with diffusing monomers. The azo-dyes perform an optically induced cis-trans isomerization. During pattern formation like a holographic grating, the local temperature increase, especially in thin films, is up to date a subject of estimation from absorption and dissipation data. However, the exact knowledge of the surface temperature would help a lot in understanding the resulting refractive index and thickness patterns during holographic exposure. In this paper, in-situ pyrometer measurements are presented. As examples, different photosensitive materials, varying from a photopolymer to polycrystalline azo dyes, are used in order to outline the magnitude of this effect and demonstrate the feasibility of this technique. 相似文献
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Infrared holographic recording in a two-step process is demonstrated in stoichiometric iron-doped lithium tantalate crystals. Through absorption of two intersecting infrared pulses (A = 1064 nm) a temperature grating and thus a modulated pyroelectric field build up. Free electrons, excited by homogeneous light of a shorter wavelength (lambda = 532 nm) drift in this field, and a phase hologram is stored that can be read nondestructively. The change in refractive index depends mainly on the absorption coefficient at the wavelength of the recording light and on the intensity of the infrared light. The proposed method may be extended to telecommunication wavelengths by choice of suitable dopants. 相似文献
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新型防潮的光致聚合物全息记录材料及其应用 总被引:12,自引:2,他引:10
本文研制出一种新型兰敏的光致聚合物全息记录材料,并提出再聚会固定全息再现峰值波长的方法.这种记录材料由增感剂,引发剂,链转移剂,单体和成膜物组成.用本材料记录的全息图衍射效率可达95%以上,且能防潮,耐高温. 相似文献
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We have observed quasinondestructive holographic storage with a continuous-wave laser at lambda = 532 nm in near-stoichiometric LiNbO3 doped with Tb and Fe. This crystal showed an exceptionally long grating decay time and also exhibited a fast color change upon exposure to ultraviolet (UV) light. It was demonstrated that the grating recorded from the UV-exposed, colored state can be continuously read out over 9 h at a reading intensity as high as 8 mW/cm(2). In addition, the written grating could be easily erased with UV illumination which returned the crystal back to the original colored state. 相似文献
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Two-dimensional (2D) polarization patterns are achieved by the interference of two pairs of beams with perpendicular planes of incidence and orthogonal polarizations (i.e. linear or circular). In both cases, imposing a phase shift of π/2 between consecutive beams contains the amplitude modulation of the optical field in the superposition region and, thus, pure 2D polarization patterns are created. The recording of these interference fields in a polarization-sensitive material, namely an amorphous azopolymer, creates reconfigurable 2D periodic microstructures with peculiar diffraction properties. 相似文献