Variation of parameters of pit deformation when recording holograms of a planar wavefront

Variation of the deformation structure of the surface of a photothermoplastic carrier is demonstrated in the case where high frequencies of an interference pattern are recorded. A smooth variation of the period of a grating projected is shown to lead to a variation of the pit diameter in a limited frequency range. A high-frequency maximum of the diffraction efficiency is observed for the deepest pits formed with the highest probability, but their size coincides neither with the maximum nor with the minimum diameter. Periodic repetition of the curve of pit growth with decreasing frequency forms additional maxima in the frequency dependence of the diffraction efficiency at frequencies corresponding to the alignment of resonant dimensions of pits in one, two, and three rows.     

数字化合成全息图自动记录系统研究

从合成全息术的编码原理出发,采用了液晶空间光调制器、步进电机控制的可移动狭缝和一维移动平台等设备以及计算机数字多媒体技术、软件编程技术设计出一套数字化合成全息自动记录系统。该系统能够改善传统全息图手工制作效率低、操作不准确产生误差等缺陷,提高了合成具有视差、动感、颜色以及不同景深等特殊效果全息图的自动化水平。实际应用该系统合成了含有40幅照片信息的全息图。     

Reflection-type polarization holograms in bacteriorhodopsin films for low-light recording

Reflection-type polarization holograms with phase-conjugated readout are very useful for low-light recording with bacteriorhodopsin (BR) films. The dependence of reflection-type holograms with parallel and orthogonal recording beams on their intensity ratio (1:1-1:20) was investigated. It was found that for orthogonally polarized beams the phase-conjugated signal depends significantly less on the beam intensity ratio than predicted by coupled-wave theory. This finding is of particular relevance for recording of very low object-beam intensities with BR films, e.g., in interferometry, where signals with a high signal-to-noise ratio, owing to the different polarizations of the scattered light and the signal, and with low dependence of the diffraction efficiency on the ratio between the reference and object-beam intensities are obtained. With this asymmetric recording process, holograms were recorded successfully in BR films with a good signal-to-noise ratio at exposures (from the object side) as low as 50muJ/cm(2) . These exposures are in the range of those typically used for silver halide films.     

模压全息图的颜色设计及其记录方法

目前模压全息广泛地应用于商品标识、卡通、贺卡等，如何制作出色彩鲜艳、亮度高、清晰的模压全息图是至关重要的。本文从两束光干涉的简单模式讨论模压全息图的颜色设计，给出几种实用的和可能用的浮雕全息图的记录方法，并介绍常用光致抗蚀剂记录材料的特性及其处理工艺。     

On the resolving power of liquid photopolymerizing compositions for recording of holograms

The effect of intrinsic concentration inhomogeneities of a photopolymerizing composition on the formation of polymeric phase holograins is considered within the framework of a diffusion model. It is shown that the limiting spatial frequency of the interference pattern recorded is determined by threshold effects for the multiplicative phase noise of the hologram and depends on the medium viscosity, the contrast, and the intensity of the acting radiation. The results of the numerical calculation are confirmed experimentally.     

Dark build-up of holograms in BaTiO3 after recording

Holograms recorded under suitable conditions in photorefractive BaTiO₃ exhibit an unusual dark build-up. The diffraction efficiency increases by some orders of magnitude after the recording beams are switched off, and then steadily decreases afterwards. An interpretation of this effect in terms of a two-center charge transport model is given.     

Lateral-shift interference patterns in the two-exposure recording of Gabor holograms

It is shown theoretically and experimentally that two-exposure recording of amplitude-scattering Gabor holograms by means of telescopic optical systems doubles the sensitivity of the interferometer with a fixed lateral shift. When the holograms are recorded by means of a Keplerian telescope, the spatial extent of the interference pattern is limited by the image of its outlet aperture.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 89–96, February, 1996.     

Analytical expressions for and geometrical meaning of the comparative indices of recording media

The indices for characterizing the performance of holographic recording media introduced recently by Tai and Yu can be related to the parameters of the optimal linear transfer function (OLTF). These parameters have been obtained in an analytical form by the author for the recording material with an exponential transfer curve and for the holographic setup using two plane waves and for the case of the fourier lensless hologram. The expressions for the indices in terms of the OLTF parameters are given and their geometrical meaning in relation to the OLTF is pointed out for the two holographic setups mentioned.     

Optimization of the recording conditions for holograms recorded in additively colored KCl crystals

The dependences of the characteristics of volume holograms recorded in additively colored crystals of potassium chloride on the spatial frequency and the recording temperature are studied. It is found that these dependences are nonmonotonic, which indicates the presence of nonlocal mechanisms of holographic recording in the crystals. These mechanisms involve diffusion and drift processes of redistribution of color centers between the nodes and antinodes of a recorded interference pattern. The results obtained are used to determine the recording conditions providing the maximum possible diffraction efficiency of the holograms.     

Calculating and matching the spatial frequency spectrum for recording quasi-fourier holograms on photothermoplastic media

We propose a modification of the optics for recording Fourier holograms. We calculate the spatial frequency spectra of the interference field. We have studied the effect of the parameters of the objectives on the spectral matching, determined by the recording optics and the resonance type of transfer characteristic for the photothermoplastic recording medium. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 124–128, January–February, 2006.     

Spectral photosensitization of a variable index material for recording phase holograms with high efficiency

The use of a photochrome as spectral sensitizer for refractive index variation by photopolymerization of acrylamide has made possible the recording of high efficiency phase holograms due to the lack of absorption in the recording medium. A resolution of better than 3000 lines per mm has been obtained.     

Non-stoichiometric barium ferrite particles for high-density magnetic recording

The organometallic precursor method was employed for the synthesis of β” ferrites, from which non-stoichiometric Ba ferrite particles have been prepared by ionic exchange. The magnetic grains are hexagonal platelets with diameters as low as 50 nm and aspect ratio of 1.5. After annealing, the sample diameter increases to 200 nm while the grains remain single-domain. The Curie temperature is 455°C. Annealed samples show specific magnetization up to 62 emu/g, coercive fields _jH_c close to 2 kOe, and an SFD factor 1−S* of 0.55     

Registration of lateral shear interferograms for the case of dual exposure recording of Gabor holograms

It is shown theoretically and by experiment that dual exposure recording of Gabor holograms of an amplitude scattering mask leads to twice the normal sensitivity for the same amount of shift in a lateral shear interferometer of axial wavefront aberrations of a controllable wavefront.Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 89–94, October, 1995.