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- Holographic Nondestructive Testing
- Coherent Optical Effects and Holography
- Recording Materials and Holography
- Recording Materials: Bacteriorhodopsin
Holographic Nondestructive Testing
Recent achievements and perspectives of holographic nondestructive testing
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Holographic interferometry can be used to examine minute changes in the surface of components as they undergo stress, thermal expansion, erosion, growth, and vibration. Such changes often can be used to identify the presence of a defect beneath the surface, because of the anomalous microscopic behavior of the surface. In addition, the mechanical characteristics of the component, such as vibrational modes, expansion, and residual stress can be identified through holographic inspection. Over the past 30 years a wide range of methods have evolved as new hardware and technology becomes available. The wide range of procedures, including electronic holography, multiwavelength recording thermoplastic recording, time-averaged holography, real-time holographic interferometry, cineholography, and other methods can be revisited each time a new development is made in lasers, computers, and recording materials. Methods that once held only academic interest often become practical with newly available hardware and software.
Preliminary considerations for the computer analysis of fringe maps generated when holographic interferometry is applied as an NDT tool for airframe structures
Jacqueline M. Mew,
John M. Webster,
Steve Hand,
et al.
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The temptation when presented with the requirement to interpret holographic interferograms of aluminum aircraft structures derived through a non-destructive testing technique is to examine the whole interferogram. Computers are renowned for their ability to process large amounts of data accurately and speedily, therefore there is a strong temptation to harness their particular powers. This is not only time-consuming and wasteful of computing resources, it is also unnecessary. However, before work can begin on interpreting an interferogram by computer the problem itself must be defined. In this particular example the interferogram is from a sample taken from one of the world's aging passenger airline fleet. The sample is from an aluminum stabilizer in which faults have been induced or have occurred during the service lifetime of the aircraft. All faults have been confirmed by destructive evaluation or by alternative techniques. Thus the problem domain is known. When a human expert examines an interferogram s/he concentrates on areas where faults are likely to occur namely, the areas immediately surrounding the stringers and frames as well as the stringers and frames themselves. The faults are typically caused through endless pressurization cycles or through corrosion. These faults have been induced to show themselves by a distinctive pattern of interference fringes across stringers and frames, where normally no fringes should be expected to occur. Therefore the human expert search concentrates on these areas, using the fringe count density or shape over the whole of the interferogram simply for comparison or control. The computer aims to emulate the human search. However, difficulties have been identified that could prove problematic for the computer that are elementary for the human brain. In our early work the sample interferograms for computer analysis have been selected because, to a human, they are uncomplicated and relatively noise-free sample in which faults are easily identified. This gives a good test case against which the computer can be compared, however the strength of the computer may finally by in interpreting holographic interferograms that are difficult for humans to interpret either though complexity or human consideration such as fatigue when hundreds either though complexity or human consideration such as fatigue when hundreds of such images are required where, for example, a large structure such as an aircraft is considered.
Panoramic interferometers for investigating deformations of cylindrical objects
Leonid A. Borynyak,
Eugene A. Krasnopevtsev
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Research methods of deformations of cylindrical objects by means of panoramic holographic interferometer and panoramic speckle interferometer are discussed.
Real-time holographic camera
Alexandr V. Stolyarenko
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Holographic camera, which makes high quality holograms using a thermoplastic photosensitized film installed on a transparent substrate with semitransparent conductive film hitter is described. The holographic camera automatically monitors exposure and development. The image on photosensitive plate can be exposed and erased many times. With optical exposure and development - about 3000 write/erase cycles are possible to realize before noticeable degradation of image. The system is OEM product.
Shape investigation of deformed bodies by adaptive base holographic interferometers
L. A. Borinyak,
O. N. Zakharov,
P. M. Mednis
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Superposed holographic interferometers1'2 are designed to investigate the displacement and deformation of the plane parts of the surface of the diffuse objects. These interferometers can register the information about the displacement of the points of the deformed surface relative to any base of the interferometer during the experiment staying practically stable because of using low modular optically transparent medium between the base of the interferometer and deformed surface. The problem appears in those cases when the thin wall construction is to be investigating of supporting the walls of construction by interferometer itself. This problem were solved by means of using the low inertial adaptive base interferometer in which were registered the information about the additional difference step arising because of angles of illumination variation in difference with former used methods of getting of information. This method allow us to construct the optical transformer in laboratory conditions separately in terms of gelatine emulsion or film and then to place their on the object's surface for the aim of control of the deformation of the objects. The interferogram may be observed as in white as well as in monochromatic light It contain in itself the information about curvature of the surface relative to basic one registered in laboratoiy conditions. The caving in process of the construction is followed by change of angle of illumination and hence is followed be change of sight of interference fringes. The structural differences of the hologram contain the information about the curvature change variation of the surface researched.
Pulsed laser holographic video
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The use of a pulse laser as the source light for a holographic video system allows to eliminate the polygon mirror or scanners in the system. At the same time, a single long aperture AOM is replaced by 6 small aperture AOMs aligned in a line. The effective aperture length of the 6 AOM combination is 6 times of that of the individual AOM. the CGH data is divided in 6 equal part s and fed into the corresponding AOM simultaneously. This new AOM structure permits to use a personal computer for data feeding.
Coherent Optical Effects and Holography
Coherent field orthogonalization with speckle-wave volume hologram
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The effects connected with the laser modes' variations at volume hologram recording and reconstruction are studied. The results of the theoretical analysis for the reconstructing wave are compared with experimentally obtained data. Photorefractive Fe doped LiNbO3 crystals are used as the recording media for volume holographic storage. Laser modes of different indices were applied at hologram reconstruction, and methods of the diffracted beam intensity enhancement are discussed.
Optical singularities are induced in Gaussian laser beams by Kerr-like medium: geometrical optics study
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The geometrical optics method permits to make preliminary conclusions about optical singularities formation and their location after specific phase object: the necessary and sufficient conditions of optical singularities existence are worked out. It was shown that the locus of optical singularities after thin Kerr-like medium shaped enclosed curves. The result agree with experiment and numerical modeling of wave equation.
Holographic memory with speckle-wave volume hologram
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This paper deals with characteristics of volume hologram recorded and reconstructed with random amplitude-phase encoded reference wave. The speckle-encoded reference wave was proposed as the method to modify selective properties of the hologram. In particular, it is demonstrated that volume holograms recorded with this type of reference beam are taking new selective features, such as the sensitivity of the diffracted beam intensity to spatial mismatch between the hologram and reconstructing beam in transversal and longitudinal direction. Moreover, the conditions can be set, when the hologram's angular selectivity is not due to violation of the Bragg conditions, but is a result of spatial angular de-correlation between recorded and reconstructing structures. The analysis is made on the applicability of these features of volume hologram for high density information storage.
Recording Materials and Holography
Chalcogenide inorganic resists as holographic recording media
Ivan Z. Indutnyi,
Peter F. Romanenko,
Alexander V. Stronski,
et al.
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In present paper the utilization of the two types of inorganic resist: Ag-chalcogenide glass (ChG) structures and thin ChG layers for holograms recording is discussed. The optical characteristics and photographic properties of these materials were investigated, the study of hologram relief formation in ChG-Ag and ChG layers have been made. Among the investigated ChG layers the As40S20Se40 have shown the most optimal characteristics for the hologram recording. Good mechanical strength and thermostability of ChG layers enabled to use the obtained phase relief holograms after additional treatment for the production thermo- or photopolymer copies, or galvanic nickel deposition. The high quality polymer copies and nickel matrixes for mass production were obtained from the chalcogenide based master holograms. Characteristics of the obtained phase-relief holograms and their copies were investigated.
New epoxy-based polymer as a recording medium for dynamic and stationary holography
Oleg M. Buryn,
Anatoly A. Borshch,
Michail S. Brodyn,
et al.
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The performance of a recently developed nonlinear optics epoxy-based polymer with covalently attached dye molecules is investigated. Large refractive nonlinearity is observed. The refractive index nonlinear coefficient and relaxation time were measured using a degenerate two beam coupling scheme with a frequency doubled Nd3+:YAG laser. We have used a thin polymer film for dynamic holography recording. Peculiarities of self- diffraction at the holograms are discussed for both dynamic and stationary hologram recording. The possibilities to write and erase phase gratings reversibly by ns-pulses and store information for hours are demonstrated. An analysis of possible mechanisms for the refractive index nonlinear behavior is presented. The results vividly manifest the possibility of the polymer to be used as reversible medium for information storage. Besides, the polymer structure in question exhibits both ns and quasi-stationary response together with simplicity of fabrication and low prises which have wide prospects for different applications in the field of optical data processing.
Thermodynamical and structural aspects of holographic recording in photopolymers
Tatiana N. Smirnova
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THe process of holographic recording in the liquid photopolymer compositions (PPC), which contain a photopolymerizable component, an initiating system and a neutral component, is described in the frame of the phase separation of the origin mixture. Experiments were performed to determine the dependence of efficiency of recording and lightsensitivity of material on the thermodynamical compatibility of the system polymer-neutral component, kinetic parameters of the polymerization process and the diffusion mass-transport, supported the formation of holograms. The two-phase structure of holograms in PPC has been observed with help of fluorescent probe method. The average size of the microphase particles has been determined. The effect of photopolymer heterogeneity on the noise characteristics of holograms and resolution of recording composition has been shown.
Kerr nonlinearity and induced optical properties in organic liquids
Olena I. Kondilenko
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The changes of the optical properties under strong field in Kerr liquids is investigated. The cases of individual molecules and molecular swarms in examined.
Optical control of the FWM dynamic grating structure in PRC with nonlocal response
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The dynamic and steady state solutions for transmission grating amplitude are obtained. It is shown that the FWM scheme provides the optical control of diffraction efficiency as well output parameters of interacting waves. The ways of increasing of diffraction efficiency are determined.
Characterization of CdTe:Fe crystals by means of transient holography
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Measurements are presented for the photorefractive grating recording under pulsed excitation in the crystal of CdTe doped by Fe. The crystal under study is characterized by high electron mobility in comparison with typcial value. The photorefractive parameters of the crystal such as gain factor, Debye screening length, effective density of charge traps as well effective electro-optic constant have been measured on the basis of gain/grating spacing, gain/crystal rotation angle at different recording beam polarizations, and gain/intensity at different crystal orientations dependencies. The electron-hole competition influence on the crystal photorefractive performance is discussed. The fast photorefractive effect was shown to occur under pulsed excitation maximum gain factor, (Gamma) , being equal to approximately 0.3cm-1 without any externa electric field. Different self-action effects accompany two-beam coupling are discussed. These are two photon absorption, free carrier generation, self-action of laser beams. The photorefractive effect was separated in its pure form from the various nonlinear optical phenomena.
Miniature integrated optic displacement sensors with holographic elements
Lyudmila I. Konopaltseva,
Nadezda P. Sytcheva
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Miniature integrated optic displacement sensors for measuring systems were developed to apply for traditional industrial optical production. Sensors provide substantial sizes and weight decreasing, exploitation properties.
Recording Materials: Bacteriorhodopsin
Real-time holography on bacteriorhodopsin-based materials
Victor B. Taranenko
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The main properties and mechanisms of photoresponse of the bacteriohodopsin-based materials are presented. Fields of their potential applications in the real-time holography and nonlinear optics are discussed.
Comparison of pulsed versus cw behavior of the diffraction efficiency of bacteriorhodopsin thin films
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The feasibility of using the organic nonlinear photopolymer bacteriorhodopsin in holographic interferometry has been of growing interest in recent years because of its real time properties and its relatively high diffraction efficiency. In this paper, a comprehensive analysis of the behavior of bacteriorhodopsin thin films under both CW and pulsed conditions will be presented. Because bR is an erasable material, a simultaneous read-write geometry was used for these experiments, and data taken as a function of both read and write parameters. In the CW case, the dynamic behavior of the diffraction efficiency has been characterized in the initial growth region, to obtain sensitivity curves, and in the decay region, to obtain the behavior of the M-state lifetime. In the pulsed experiments, the behavior of the material was observed in the growth region, to study the reciprocity behavior of the material. From the data, a comparison between the behavior of the diffraction efficiency was made for pulsed and CW illumination, in terms of diffraction efficiency, sensitivity, and the time-dependent M- state population.
Anisotropic nonlinearity of concentrated bacteriorhodopsin suspensions
Victor B. Taranenko
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Experimental results for concentrated bacteriorhodopsin suspensions on light-induced dichroism/birefringence and change of scattering light structure are reported which indicate that a photoselective orientation of purple membranes occurs in this material in addition to well known process of photoselective bleaching of bacteriorhodopsin molecules.
Analysis of object motion by dynamic holography recording in bacteriorhodopsin films
Nikolai M. Burykin,
Elena Y. Korchemskaya
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It is proposed to combine the real-time testing of the dynamic holographic grating with self-diffraction registration of this grating in Raman-Nath conditions in order to detect the photorefractive variations which accompany the proton transport through the rigidly-held fragments of purple membranes containing biological photoreceptor bacteriorhodopsin (BR). The properties of superfast holographic recording on BR-films in Raman-Nath conditions are applied for an analysis of the object motion with cycle processing time of less than 1 ms. Whereas most of the holographic methods are based on dynamic holography recording in photorefractive materials with local response in Bragg conditions. The analysis of the object motion in the first-order diffracted beam in Raman-Nath self-diffraction conditions offers a number of advantages: 1 ) there is not the problem of the suppression of high undiffracted beam; 2) the registration of start and final of a object motion with very high precision; 3) the separation of the forward and reverse motions, even after a time it is possible to detect what motion direction was initial; 4) the low-frequency and high-frequency components of a object motion are selected and their mutual direction are determined.
Keywords: biological photoreceptor bacteriorhodopsin (BR), polymer films with BR, proton release, Raman-Nath self-diffraction conditions, first-order diffracted beam, analysis of the object motion, motion direction separation, motion frequency selection.
Keywords: biological photoreceptor bacteriorhodopsin (BR), polymer films with BR, proton release, Raman-Nath self-diffraction conditions, first-order diffracted beam, analysis of the object motion, motion direction separation, motion frequency selection.
Real-time selective image processing using photoinduced anisotropy of bacteriorhodopsin polymer films
Elena Y. Korchemskaya,
Dmitriy A. Stepanchikov
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Two different methods can be used for photoinduced anisotropy in the bacteriordopsin (BR) polymer films. The first method is based on the anisotropic properties of the initial photocycle form bR570, and second method is based on the anisotropic properties of the longest-lived photocycle intermediate M412. The mixed B-M-type photoinduced anisotropy holds much promise for an implementation of the devices capable of controlling light with light. The possibility of the application of BR polymer films for the light polarization modulator with purely optical control, photoanisotropic incoherent-to-incoherent optical conversion with concurrent spatial intensity filtration, and for logical image processing are shown.