reflection of electromagnetic waves from amplifyng medium

a.a.kolokolov, g.v.skrotsky

a reflection of light from a flat surface of the semi-infinite homogeneous amplifyng medium is considered and the reflection coefficients for monochromatic plane waves are found. from the obtained results it follows that sommerfeld's radiation principle is invalid for the infinite amplifyng media. possible explanation of the results of experimental measuring of the reflection coefficients for the active media is made on basis of the developed theory.

diffraction theory ot holography

v.v.aristov, g.a.ivanova

the present paper deals with diffraction theory of holography. the consequences of the theory were analized. it was shown, that in holographic schemes, satisfactorily described by this theory, reconstruction of the images/Image is possible only at definite positions of reconstruction wave. the holographic scheme without reference wave was analized. it was shown, that by hologram of intensities it is possible to reconstruct the images/Image with the requirements for stability being more simple, than in schemes of common holography.

a theoretical model of the holographic synthesis of 3d x-ray images is proposed. on its basis it is shown, that assuming the specific syntheses conditions the false images/Image field is equivalent to the object material density and creates the observation illusion of the object internal structure from the x-ray source side. the real reconstructed images/Image allows to obtain tomographic images of the object. the calculated properties of the ideal synthesizsd images are in good agreement with the experimental ones.

the kirchhoff-kottler electromagnetic diffraction integral has been considered. paraxlal approximation of the latter is used in the theoretical substantion of the method of polarized holographic recording.

the further theoretical development of the method has been carried out. the following items have been discussed: the general case of the condition of the reference beam polarization, the recording in complex weigert effect (birefrigence + dichroism) and the recording in combined actions of complex weigert effect and complex scalar photo chemical effect, which is of the gratest interest from the standpoint of real photoanisotropic materials.

experimental results of the polarized holographic recording are carried out which are in close agreement with the developed theory.

the method of the optical reconstruction of object by measuring the autocorrelation function of far-field radiation are considered. the methods are based on application of the exponential filtration of recived signal and noncoherent reference source. the possibilities of using the intensity interferograms for this purpose are analysed. the distortions of the reconstructed images/Image due to nonmonochromatic sources are estimated.

a new method characterising properties of holograms is presented. the mathematical description of interference pattern structure is given in terms of the group theory. a group theory model of hologram is considered.

a total group classification of holograms is described. it is shown that the prognostic of the new type of holograms is possible. exemples are given to show how the group theory model of hologram can be used.

under discussion is the potential part of the waves fields quantum nature in holography. for the electromagnetic field the part of the quanta absorbtion noise is evaluated and the dependent on the vacuum quantum electromagnetic field principal limit of the information capasity of the holographic channel is evaluated.

the probability of modelling of the optical filtration process is considered. there is given a solution of the problem of recording optimal choice (relation between the intensities of recording beams and exposure time) with regard to real characteristics of photomaterial and to filter present parameters (selectivity and differential efficiency). as an illustration the filter optimal parameters are calculated to solve the problem of centrally-symetrlcal object distribution (circules of differefat radii simulating bacteria colonies).

prospects of holographic interferometry as compared to the classical interferometry are considered. it is indicated that in holographic interferometry the type of objects under investigation has been extended significantly, including diffuse-reflective objects, however, methods of the classical interferometry based on shearing interferometry and interference comparison with a reference specimen appeared to be inapplicable to diffuse-reflective objects and in holographic interferometry. a new trend in holographic interferometry is described which is based on correlation of the intensity of diffuse-coherent radiation and which overcomes the above restriction. some problems of calculation and technique of holographic interferometry are but briefly discussed.

main sources of errors of measurements of surface displacements of diffuse-reflective objects by the holographic interferometry method are analysed. relationships between errors of determining displacements and errors of directly taken values are obtained. the presence of a systematic error of measurements dependent of averaging the interference images/Image over the aperture of the registering optical system is indicated; its dependence on the apperture and displacement vector is obtained and the method for taking it into account is given. for a specific holographic scheme estimates of a mean square error of determining displacements are arrived at.

the number of different methods to produce replicas of holograms are compared, and certain application fields are determined.

the equation to produce thin replica by interference technique is given. the effects of type of the original hologram, the spacing between the hologram and replication material, the form of replication wavefront, and the wavelength of the replicating radiation on the properties of interference replicas are discussed.

the equations to determine the spacing between "the duble images", reconstructed by thin replica, are obtained.

the experimental results of replication of the pattern fringes of fourier-mlcroholograms of technical documents are given.

some holographic methods for getting of the precise parameters of phase-exposure dependence of recording media are described. intel-modulation noise is shown to be is under the most influence of the material nonlinearity, while the nonlinear distorslons of half tone could be decreesed by particulary compensation of the intrinsic nonlinearity of a thin phase hologram with material nonlinearity.

results are reported on theoretical and experimental investigation of coherence properties of the injection semiconductor laser's emission. a possibility is shown for hologram recording, holographic interferometry, single-pulse holography and reading-out of information stored at a density of 10⁵ bit/mm² using semiconductor laser.

some formation features of quasi-optical radioholograms registered on discrete and continuous recording media are considered. moreover, some principles of synthesieing radioholograms of objects moving with respect to the receiving and transmitting antennae are discussed.

holography used to recommend etalons of complex form is considered. some technical difficulties of the method and ways of their overcoming are discussed.

the photographic properties of the new holographic film fpg-v2 and the method of its treatament to obtain maximum value of diffraction efficiency are described.

in the present paper it is reported about the properties of photographic materials for recording of laser radiation in the region of 0,69 mkm, 0,84 mkm and 1,06 mkm.

the review of the holographic performances of erasable (organic and inorganic photochromic materials, electro-optic crystals, photothermoplastics, elastomer devices, magneto-optic materials, liquid-crystal systems, absorbing liquids and semiconductor crystals, chalcogenide fims, and glasses) and irreversible (photopolimers, photoresists, gelatin-di-

chromate layers, metal-semiconductor systems, metal films) holographic light sensitive recording media is present. perspectives of the improvement and possibilities holographic applications of this materials are discussed.

some performance peculiarities of thermoplastic media /tm/ at registration and reproduction of optical holograms are stated in the work.

the spectral sensitive region, latent imaging, development and transfer function are considered.

on the basis of analysis the conclusion io drawn that the tm may register optical holograms over the whole visible and near infrared and reproduce the holograms in the real time scale. spacial frequency band of the transfer function is determined by rheological properties of the thermoplastic layer and controlled by the surface potential rate of temperature increase and time of development.

this paper is devoted to the main properties and some characteristics of the new photographic materials. this materials worked out on the effect of the photographic light-sensitive semiconductor-metall systems discovered by author and his collaborators.

the preparation, use, general properties and review the processe of hologram formation in several of the most promising new organic holographic recording materials (photoresist, photopolymers, free-radical photographic systems) are discussed, and relevant experimenta data for important holographic parameters auoh as difraction efficiency and modulation transfer function are presented.

the holographic properties of the organic and inorganic photochromic materials are reviewed. result of the applications of some materials in holographic devices are discussed.