Ana Purtseladze

Recording and reconstruction of a polarization is analyzed theoretically in the cases of completely polarized and completely depolarized source of light. Reconstruction of an image is shown to be adequate in the state and degree of polarization, in both cases, when certain restrictive conditions are imposed upon isotropic, anisotropic and gyrotropic reactions of the polarization- sensitive medium. Realization of the extended concept of an a posteriori experiment is impossible when recording is  made with completely polarized light. When unpolarized light is used, the Jones matrix of the hologram responsible for the image reconstructed turns out to be equal to the Jones matrix of the object itself with an accuracy to a constant factor. Hence, it follows that illumination of the hologram with any wave of a given polarization produces a reconstructed field of the object identical in polarization to the field of the object illuminated with the same wave a priori .The realizability of the extended concept of an a posteriori experiment as related to polarization characteristics of the wave field of a hologram is established. The utilization of the method described for holographic copying of polarization devices of arbitrary types is argued, and the advantages of such copies are described.

The model consideration of the description of polarization state of light is received when fully polarized light passed through a nonstationary anisotropic device is presented. In this case fully polarized light becomes partially polarized. It is shown that the degree of the polarization of light is immediately connected with the time profile of nonstationary process.

განხილულია სინათლის პოლარიზაციის მდგომარეობის ცვლილება არასტაციონარულ ანიზოტროპულ არეში გავლის შემდეგ. ორმაგი სხივთტეხის კომპლექსური კოეფიციენტი აღწერილია დროში სინუსოიდალური ცვლილების კვადრატული ფუნქციით. ნაჩვენებია, რომ მახასიათებლების გარკვეული მნიშვნელობებისათვის მოცემული არე იწვევს თავდაპირველად სრულად პოლარიზებული სინათლის სრულ დეპოლარიზაციას.

The formation of an image by a wave conjugate to the reference wave is considered theoretically. It is shown that the polarization hologram formed upon summation of two beams with mutually orthogonal circular polarizations does not yield conjugate or ghost images in the course of reconstruction. The application of the photoinduced anisotropy in polarization-sensitive dynamic media for the correction of laser radiation with a complex polarization distribution over the wavefront is proposed and tested experimentally. The installation of polarization-holographic correctors both outside the cavity and in the intracavity volume of the laser provides the possibility of achieving divergences close to the diffraction limit at a high energy output.

A theoretical approach is developed that provides the possibility of representing partially polarized radiation in the form of a sum of mutually orthogonal polarized and incoherent components and in the form of a model device with a time-dependent circular birefringence. This approach allows one to apply the vectormatrix Jones method in calculations. The possibility of theoretically determining the degree of polarization of the light passed through a corresponding device placed in an external magnetic field is shown as an illustration.

We present the results of our investigation of photoanisotropy and photogyrotropy in the compositions of several dye mixtures in a polymer matrix. A variety of light-sensitive media are available today in which polarized light induces photophysical and photochemical processes that result in photoanisotropy and photogyrotropy. Among these media the materials on the basis of organic dyes in a polymer matrix are available. The photochemical behavior of single dyes usually differs from their behavior in mixtures; it is, therefore, natural to assume that photoanisotropic properties of dye mixtures will also differ. Based on these assumptions we created several compositions of organic dyes from different classes. The physical and chemical properties as well as the mechanisms responsible for anisotropy of the dyes used in this investigation differ significantly. A special technique was needed to make the most of their photoanisotropic properties. 

Of the various polarization sensitive media, those based on organic azo-dyes continue to attract the interest of researchers because of an entire range of advantages: a large assortment of manufactured dyes, polarization sensitivity over a broad spectral range, the possibility of controlling the photoanisotropy and photogyrotropy parameters by physical and chemical processing, the ability to synthesize new dyes with predictable polarization sensitivity parameters, etc. These studies have shown that the polarization sensitivity of these media depends on many factors, primarily on the structure of the dye and the chemical activity of the matrix, but also on the technology used to fabricate the media, the form of solvent, rigidity of the matrix, latensification, spectral composition of the activating radiation, etc. [4, 5]. Here we study photoanisotropy and photogyrotropy in media based on mono-azo-dyes vof methyl orange and its homologs, including specially synthesized one, in order to clarify the effect of the complication of the molecular skeleton on the photoanisotropy and photogyrotropy of dyes in a neutral medium, as well to clarify the effect of the acidity of a

Solvent on the polarization sensitivity of these molecules when they are exposed to actinic linearly polarized light. The resulting data are analyzed. 

This is an experimental study of the photoanisotropic gyrotropic properties of recording media based on azoindicators ‒ homologs (five dyes) of methyl orange ‒ introduced into the polymer matrix. Samples were prepared by a technology we have developed employing solvents with different acidities (pH 1.68–12.48). The samples were exposed to actinic radiation (λ= 488 nm) from an argon laser, and the photoinduced anisotropy measured in real time. The circular dichroism and circular birefringence in the layers under study are calculated for a neutral medium and at different pH levels.

The polarization properties of reflection Denisyuk holograms produced in a photo-anisotropic gyrotropic material by an unpolarized coherent light source are studied experimentally. The polarization state of the reconstructed image is found to depend on the polarization of the reproducing beam (polarization holographic memory). This effect is examined theoretically. Under certain limiting conditions on isotropic, anisotropic, and gyrotropic reactions of a polarization sensitive medium, the recovered image can be adequate with respect to the state and degree of polarization. When unpolarized light is used, the Jones matrix of the hologram responsible for the reconstructed image is equal to the Jones matrix of the object itself to within a constant factor; that is, illuminating the hologram with a wave of specified polarization yields a reconstructed field of the object that is identical, in terms of polarization, to the field of the object illuminated a priori with this wave. This method has been used to reproduce the degree of polarization of a partially polarized wave field and to study the polarization holographic characteristics of a photoanisotropic gyrotropic material.

Sensitized photoanisotropy induced in fi ne-grained silver-halide photoemulsions was investigated using VRP photoplates as an example. Various factors including the photoemulsion type and the preliminary treatment of unirradiated layers (hypersensitization and/or heat treatment), actinic exposure by polarized radiation, development, and fixing were shown to influence the photoanisotropy parameters (light-induced birefringence and anisotropic absorption).

The luminescence polarization properties of new recording media obtained by directed synthesis—disulfochlorides of luminescent dyes (homologues of 1,7-diamino-3,9-dihydrodibenzo-[1,2,3de:4,5,6- d'e']diquinoline-2.8-dione (1,5-diaminoanthradipyridone) series), with the general structure (ClSO2)2-1,5-di-AAP-di-R—are investigated. Polarized photoluminescence spectra are recorded, and spectral dependences of the degree of anisotropy of phosphor on its chemical structure at different acidities of the medium are plotted.

The photoanisotropic properties of polarization sensitive luminescent media applied in holography based on bituminous materials are studied. The effect of photoluminescence memory of the excitation linear polarization in Georgian crude oils and motor gasolines with different octane numbers is revealed. Photoluminescence and polarization spectra are obtained, and polarization characteristics of media depending on their chemical structure and composition are measured. A Denisyuk reflectance hologram is obtained in a luminescent photoanisotropic gyrotropic material using the linearly polarized coherent light, and its polarization characteristic is studied.

Wines have been identified and classified on the basis of joint processing of various types of polarization spectra of Denisyuk multiplex dynamic luminescent holograms obtained from samples of studied wine products (specific wine brands). The luminescence spectrum of the restored imaginary image of the object, spectrum of the degree of anisotropy of the luminescence of the object reconstructed field, and spectrum of the ellipticity coefficient of the luminescence of the object reconstructed field have been selected for the analysis. An experimental study of the polarization properties of Denisyuk multiplex holograms obtained in a luminescent photonisotropic–gyrotropic material using a linearly polarized coherent light source has been conducted. Polarization-holographic memory has been observed. An experiment on the identification of samples that was conducted to test the possibility of using polarization spectra for wine recognition has been described.

Polarization-sensitive hologram media based on polyvinylpyrrolidone and gelatin matrices, into which the Lucifer Yellow and Coumarin 466 dyes have been introduced, have been created. A Denisyuk multiplex dynamic hologram has been recorded using linearly polarized LSR 405 NL-50 laser radiation (λ = 405 nm) in a luminescent photoanisotropic gyrotropic material. The photoanisotropic characteristics of the beam corresponding to the reconstructed virtual image of the object field have been measured by polarization-luminescent holography. The polarization spectra and photoluminescence intensity spectra of the reconstructed image have been measured, depending on the recording medium composition. The possibility of multiplex recording and observation of several images of an anisotropic gyrotropic object simultaneously if they are encoded by different emission frequencies and/or polarization state, has been shown. The combination of nondestructive polarization-luminescent holographic measurement method with other luminescent spectroscopic methods significantly expands the scope of this method and dramatically increases the overall information content of the study.

Photoinduced gyrotropy (nonlinear optical activity) of polarization-sensitive luminescent recording materials based on various drinking and mineral waters are herein studied by polarization-luminescent holography methods. Photoluminescence spectra and spectra of the degree of circularity of (circular) polarization luminescence of areconstructed phantom object are obtained. A significant modification of the dynamic multiplex luminescent Denisyuk holograms is observed in the medium during the transition from the racemic to chirally pure phases. In particular, a polarization-holographic memory of the gyrotropic properties is expressed in the considered aqueous media. Polarization-holographic analysis of the optical polarization spectra of the aqueous media makes it possible to obtain additional information about anisotropic-gyrotropic holographic materials, namely, the intrinsic chirality of the components of each compound present in the medium.

The phenomenon of photoanisotropy and photogyrotropy in various light-sensitive regions has recently been frequently used in information processing and polarization holography tasks. The mechanism of the mentioned event is related to the photochemical and photophysical transformations of molecules under the influence of actinic light, as well as nonlinear optical events. The latter removes wide opportunities for the detection of anisotropic bleaching phenomena in photophysical processes. Induced birefringence and anisotropic absorption dispersion curves at the extreme absorption region (650-750 nm) of selenium-cadmium glass are obtained. The possibility of using photoinduced anisotropy in selenium-cadmium glass for correction of laser-generated radiation in case of complex, non-uniform distribution of polarization state on the wavefront is experimentally tested. By placing the polarization-holographic corrector in the space of the optical resonator, the diffraction-limited resolution of the light cone is achieved, with a high energy output.

Existing methods of system analysis of partially polarized light are based on the so-called coherence matrix. Correlation functions which are the elements of this matrix make it possible to completely analyze optical experiments in the case of stationary fields. Similar functions are also used in analysis of non stationary fields; however, in this case, these functions should be determined in terms of quantities averaged over an ensemble, rather than over time, which requires considerably more complicated mathematical tools. Moreover, the coherence matrix does not yield a particular mechanism for the formation of partially polarized light. In [1, 2], a new theoretical approach to the problem of partial coherence has been proposed, which makes it possible to represent partially polarized radiation as a result of the action of some model device with time dependent optical anisotropy on the initially completely polarized light. In this work, this approach is further developed, and the operation of a non stationary model device with a circular birefringence is analyzed theoretically.A new theoretical approach to describing the state of polarization of radiation formed by a non-stationary system and determining the degree of polarization is proposed [1], where partially polarized radiation is presented as the result of the interaction of a model system with time-varying optical anisotropy and initially fully polarized radiation. The degree of polarization of the formed field is determined directly related to the time profile of the anisotropic characteristics of the system.

The paper describes the results of experimental research for the creation of a three-dimensional information carrier of a large-capacity polarization-holographic memory system with standing waves. In order to obtain reflective polarization holograms, the phenomenon of photoanisotropy in aluminoborosilicate glasses identified in [5] is used in the paper. The photosensitivity of the used material is of the order of J/cm2. Recording was done for the mentioned material with an actinic helium-cadmium laser (632.8 nm).

The possibility of applying the photoinduced anisotropy in dynamic polarizationsensitive media for the correction and amplifications of the laser radiation with a complex distribution of the polarization state over the wavefront is tested experimentally.

Anisotropic change of the absorbtion edge of seleno-cadmium glass under the action of linearly polarized monoimpulse of a ruby laser of great power has been investigated. The spectral width of the area of anisotropic bleaching of the sample which is being radiated has been estimated. The dispersion curves of photoinduced birefringence and the anisotropy of the absorbtion on the absorbtion edge of the glass of RY-19 type have been obtained in the interval (6500-6700 A).

The results of investigation of the phenomena ISPh was reported. It was shown that in the given layers after the irradiation of the polarized light with wave-length actinic for the given sensitizer and of the following specific development the photo-induced anisotropy was visualized. It turns out that weakly expressed anisotropy of the latent

image multiplied more than on the two order of magnitude. As it was shown in this investigation, the value of the photo anisotropic parameters can changed in wide-ranging after the specific physicochemical treatment: hypersensitizing, specific worked out developers, thermal treatment, fixing (in case of need). Each of the procedure has such essential value, that the separated examination was needed. For example, 20 developing agent per se and large quantity of the different compositions, and also the quantity hypersensitizers was investigated. The photo induced anisotropy maybe measured on the modified spectrophotometers SF-10 or SF-18. To receive experimentally the dependence of the anisotropic absorption, and the light induced birefringence it is necessary to carry out not less than 6 measurements of transmission of the differently oriented irradiated samples (0°; 45°; 90°), placed between parallel and crossed polarizers in the spectrophotometer. Some technological regimes which reduced to the optimization of the parameters of the photo anisotropy are presented. The high stability, the possibility of working in the red region and with the low power energy sources, with the wide controlled characteristics are represented the main advantage of such media. In addition he Schwarzchild effect in the ISPh phenomena is considered.

Azo indicators are well known in which when changing aciditythey changes their properties. It was natural to expect also their appreciable changes of their polarization properties. The results of the carried out experimental research in recording media on the basis of azo indicators– homolog of the Methyl orange introduced into the polymeric matrix are presented in this work. According to the technology developed by us, the samples for the reception of which solvents with various degree of acidity, within values pH 1.68-12.45 have been created. Samples were irradiated by the light of argon laser (488 nm) actinic for them. Measurement of light induced anisotropy was carried out on a registering recorder and can be described by means of one parameter- the effective anisotropy. As standards the samples of dyes for the reception of which neutral solvent was used have been considered. In a number of dyes the values of effective anisotropy in alkaline and acid media exceed its values concerning corresponding standards. The higher homolog – Heptyl orange and Benzyl orange which are weak or insoluble in water, become water-soluble when using solvents both with acid and alkaline reaction. The interval of appearance of light induced anisotropy has been expanded. We have used the method of the zero-ellipsometry for the research arising in the same samples light induced gyrotropy. Values of circular dichroism and circular birefringence in investigated layers in neutral media have been calculated also at various values pH. In the work the received results are discussed and analyzed.

The paper discusses the polarization properties of the compositions of the photosensitive media. The compositions have been developed - the transparent polymer in which activators were added: photoanisotropy, chiral and fluorescent impurities. Activators photo anisotropy were based on the organic dyes of different classes. Optical schemes have been created, which allows us to explore the polarized luminescence, and conduct the ellipsometric measurements of the photo anisotropic parameters obtained compositions. For polarized radiation were used standard lasers with wavelengths: (λ = 405, 441.6, 532) nm.

Nowadays, the holographic methods of information saving and processing is one of the most attractive and efficient. The advantage of the holographic method lies in the feature of holograms – ability to reconstruct information arrays, recorded throughout the hologram volume, at a high speed. This provides reliable and high-density information recording. This method enables making recording and reconstruction of the object wave polarization state, and thus has greatly increased the possibilities of holographic science. In our opinion, the next step in the development of polarization holography could be a polarization-fluorescent holography. The implementation of the polarization-fluorescent holography will enable to record information almost for any spectrum region (within the absorption spectrum of the particular medium) and its reconstruction in the desired spectral range (within luminescence spectrum), according to the given task. As known, the analysis methods based on the polarization fluorescence phenomenon, are the most sensitive and highly effective tools for modern researches. For solving problems of polarization-fluorescent holography we need a fluorescent recording medium that should have high values of quantum efficiency, high photosensitivity and must show the notable polarization-luminescent properties in the required spectral range. It is known, that the luminescent emission of many substances is, fully or partially, polarized either linearly or circularly due to the anisotropy emergency at elementary acts of light quanta absorption and emission, during the luminescence process. In most cases, the luminescence of the complex molecules is linearly polarized (as a rule, partly linearly). In case of the gyrotropic substances, characterized by ability to rotate the polarization plane, and which reveal a circular dichroism, the partially circular polarization of the luminescence is detected as well. The aim of this work is to create a new type of recording media for fluorescent -polarization holography and study of their polarization- luminescent properties.