ზურაბ ვარდოსანიძე

The problem of holographic recording and reconstruction of the first three parameters was practically solved by using ordinary light-sensitive materials, which respond only to the Intensity of light. As to the fourth parameter - the polarization the problem of its adequate recording and reconstruction was not solved. It is natural that, in the case of the usual photosensitive material, all the characteristics of the wave, except polarization, are displayed as the distribution of isotropic optical properties. However, in the general case of holographic recording the light wave, scattered on the object, changes the polarization. Therefore the total interference pattern will have the modulation also with the polarization, the information about of which is lost during the holographic recording in the ordinary photographic materials.

The laser active structures with spatial modulation of lasing controlled by the transversely distributed excitation are implemented. The dye-doped cholesteric liquid crystal (DD CLC) and polymer were used as a laser active medium. The interference pattern of two coherent pumping beams was used for excitation of the laser layers. The second harmonic of a Q-switched Nd:YAG laser (532 nm) was used for the pumping. The interference pattern of the pumping light was located in the plane of the laser active layer. The emission of lasers was observed perpendicular to laser active layers from the opposite side of the incidence of the pumping light. The periodical character of the modulation of intensity along cross section of the lasing depends and corresponds to the parameters of the interference pattern of the pumping. So, the emitted light field qualitatively looks like a diffraction from an elementary hologram, and obtained lasers can be called as active elementary hologram.

A simple analysis of the possibility of creating a holographic chiral structure on the basis of Weigert's effect with help of the Jones vector–matrix method was done, to my knowledge, for the first time. A corresponding experiment was also conducted. The results of the investigation show that the diffractive optical element obtained behaves similarly to liquid crystals or sculptured thin films with chiral structures.

The holographic recording on the photosensitive medium with Weigert's effect in the general case of linear polarization of the object wave is investigated theoretically and experimentally. A simple analysis shows that it is possible to record and reconstruct the plane lightwave with all possible linear polarization in this case. The experiment con- ducted confirms rather well the analysis results. For the first time, an investigation is carried out in the case where the linear polarization changes continuously along the cross section of the object wave, which is important for some practical applications in the problems of optical memory and optical information processing. 

The dynamic process of the multiple generation and deletion of anisotropy with linearly polarized actinic light is investigated experimentally in azo-dye-colored gelatin. The results of the investigation are in good compliance with the possible mechanism of anisotropy generation in the azo-dye-colored materials proposed by the author.

The dynamic process of highly efficient holographic recording of two orthogonally circularly polarized plane light waves on the azo-dye-colored gelatin with powerful Weigert's effect is investigated. The investigation has shown that at some ratios of the intensities of the recording waves the self-recording phenomenon during the reconstruction process by the same actinic light is observed, and the diffractive efficiency for the probe light of an already fully recorded hologram increases again almost instantly after blocking one of the recording beams of low intensity. The maximum diffractive efficiency reaches 40%–45% in this case.

The concept of a gradient-oriented state of polymers is formulated for the first time and some regularities of the formation of this state are established. The specific influence of non-homogeneous mechanical fields is demonstrated by means of the example of the creation of gradient birefringence (GB) elements. These are the focus of research into the new non-traditional direction of gradient birefringence (GB) optics. Possible areas of application for GB elements are polarized compensators, polarized holography and photonics, the interference-polarizing GB monochromator, luminescence analysis, etc.

A new type of lasing was obtained on the basis of a dye-doped cholesteric liquid crystal laser with transversally distributed excitation. Two coherent beams of the pumping laser formed an interference pattern in the planar dye-doped cholesteric layer and provided laser generation in the separate narrow strips of the pumped area. Each of the strips demonstrated lasing along the cholesteric axis. But, due to the mutual coherence of the separate strips emission, the total picture of lasing represented an interference pattern. Thus, in contrast to the conventional lasers, the intensity distribution in the laser emission pattern had a periodical character similar to diffraction from an elementary dynamic hologram.

Spatial modulation of laser emission controlled by the structure of excitation light field was demonstrated. A dye doped polymer film as an active medium was sandwiched between two laser mirrors forming a laser cell. The pumping was performed by an interference pattern formed with two mutually coherent beams of the second harmonic of a Q-switched Nd:YAG laser (532 nm) and located in the plane of the laser cell. The laser emission was observed normally on the plane of the cell. The cross section of the obtained laser emission was modulated in intensity with an interval between maximums depending on the period of the pumping interference pattern. Thus, the emitted light field qualitatively looks like diffraction from an elementary dynamic hologram, that is, a holographic diffraction grating.

The difference in the absorption of two orthogonal linear polarizations was first observed in the investigation of the total internal reflection from the interface azo dye doped gelatin layer air. This means that there exists a predominant orientation of dye molecules in the emulsion layer. It is very important fact for the problems of adequately holographic registration of polarization characteristics of the light fields. It is especially important also in the creation of holographic diffractive structures with anisotropic structures. Experiment was performed for the actinic radiation of the He-Cd laser for two mutually orthogonal linear polarizations of the light: with oscillations of electric vectors parallel (P polarization) and perpendicular (S polarization) regarding to incidence plane. The result of investigation has shown the difference of total internal reflection for these polarizations at the initial stage of irradiation of azo-dye doped emulsion layer at the incidence angle of the light 45 0 . 

A complex experiment was carried out for the first time by combining holographic and photographic recording on the registering medium. The aim of the work was the verification of the relevant assumption and in general observation of influence of additional modulation on the diffraction characteristics of the holographic structure. For the beginning the recording of the elementary hologram (diffraction grating) was performed and following photographic recording, i.e. photographic image imposition. As a result was obtained a contrast inverted image of the object without spatial filtration or phase contrast method by the diffraction on the superimposed to each other holographic phase grating and the phase image of the object. The sequentially holographic and photographic recording at the same area of the dichromate gelatin layer (DCG) was performed for this. 

Was investigated experimentally the spectral and spatial characteristics of the radiation of a light-excited layer of an alcohol solution of the laser dye Rhodamine 6G (R6G) of rectangular and round geometric shape. The investigated layer is a part of the dye solution that is in direct contact with the bottom of the optical cells, the rectangular and circular sections of which determine geometric shape of the layer. Excitation of the layer was performed perpendicular to this layer by the second harmonic of the Nd+: YAG laser (λ = 532 nm) from the side of the cell bottom. Sufficiently strong, spectrally narrow-band radiation with a circular uniform distribution of intensity around the cells, in the plane of the luminescent layer, with a small divergence in the perpendicular plane was observed. It turned out that within the concentrations of the dye in the solution from 0.12w% to 0.03w%, the following processes are observed: Planely directed uniform, in intensity, radiation around the cell in the plane of the luminescent layer with a small vertical divergence; An increase in the amplitude of radiation pulses with a decrease in the concentration of the dye in the solution from 0.12w% to 0.03w%; Shifting of the maximum of the emission spectrum to the short-wave region and significant narrowing of the radiation spectrum and decrease of the vertical divergence of radiation.

We have developed a cholesteric liquid crystal (CLC) mirror-based innovative model for detection and visualization of images in turbid media. Due to its unique optical-polarization properties, the CLC mirror is suggested as the basic element of the imaging Stokes polarimeter. The particular design of the proposed polarimeter, coupled with its distinguished operational simplicity, reliability, and real-time operational facilities, promises to fabricate a new generation of the imaging Stokes polarimeter, which can find applications in areas such as diagnostics, biology, astronomy, and remote sensing.

Homogeneous light excitation of the Rhodamine 6G laser dye alcohol solution layer of rectangular and circular geometric form by the second harmonic of Nd:YAG (532 nm) laser is realized. A circular, plane- directed radiation from the edges of the excited layer with a small, vertical, divergence was obtained.

Was investigated experimentally the spectral and spatial characteristics of radiation. The investigated layer is a part of the dye solution that is in direct contact with the bottom of the optical cells, the rectangular and circular sections of which determine geometric shape of the layer. Excitation of the layer was performed from the side of the cell bottom. It turned out that within the concentrations of the dye in the solution from 0.12w% to 0.03w%, the following processes are observed: Planely directed uniform, in intensity, radiation around the cell in the plane of the luminescent layer with a small vertical divergence; An increase in the amplitude of radiation pulses with a decrease in the concentration of the dye in the solution from 0.12w% to 0.03w%; Shifting of the maximum of the emission spectrum to the short-wave region, significant narrowing of the radiation spectrum and decrease of the vertical divergence of radiation.

The eye is considered as a vibrating combined shell, consisting of two or more chambers of different curvature, filled from the inside with an elastic substance. In addition to the functions of optical vision, the properties of the eye as the mechanical resonant vibrator, which can emit and receive acoustic signals, are discussed.