It is well known [1-3] that optical properties of ionic crystals depend strongly on the shape and the size of the crystals. In the simplest case when a sample is a slab or a film with the optical thickness nd A, where n is the refractive index, d is the film thickness and is the light wavelength in vacuum, size effects were investigated both experimentally and theoretically. In infrared reflection - absorption (RA) spectra and in spectra of thermostimulated emission of infrared radiation by thin films deposited on a metal substrate only radiative surface polaritons were observed whereas in Raman spectra, in . contrast to infrared spectra, transverse and longitudinal optical phonons were observed [4-6J. At the optical thickness of films md << A the sample under investigation looks like the Fabri-Perot cavity. For such sample a set of bands Wm appears at the frequencies Wm < WTO and Wm < WLO in infrared RA and in thermostimulated emission spectra [6,7] . These bands correspond to radiative states of the electromagnetic field in a film, i.e. to cavity modes [6-9]. The shape of these bands, their frequencies and intensities are well described theoretically within the framework of linear crystal optics if macroscopic dielectric functions of a film and a substrate and experimental geometry are known [6,7]. It is well known that thermal vibrations of ions and electrons inside a substance of a cavity are accompanied by generation of an electromagnetic field at the frequency of these vibrations,and this electromagnetic field under certain conditions can leave the cavity if the cavity has a semitransparent wall. An analogous situation should also take place for surface (interface) vibrations of ions and electrons in the substance. They also should generate the electromagnetic field. Electromagnetic waves with q < k0 will be radiated into empty space, whereas those with q < k0 will be "tied" to the surface. As a rule surface polaritons of dielectric and semiconductor crystals and surface plasmon polaritons of metals are considered as nonradiative excitations because their wave vectors q are large than wave vector of light in a vacuum k0 [10]. Nonradiative surface polaritons with q < k0, generated by thermal motion of surface atoms and electrons of crystals, can be converted into light by means of an ATR prism brought to the crystal surface [6,7] . The ATR prism placed near the surface of a crystal turn the nonradiative vibrational surface states of the crystal — vacuum interface with q < k0 into light absorbing (radiative) states. The presence of a prism near the crystal surface leads to a perturbation of surface polaritons and, as a result, to a considerable change in the dispersion law [6,7,10]. Radiative decay of these polaritons, i.e. their transformation into light, is detected experimentally. Thus, in addition to conventional anharmonic decay of elementary excitations in a crystal there exists an additional decay channel: a radiative channel. Namely due to the radiative instability of polaritons their interaction with the external electromagnetic field, i.e. light, is possible. In this report we consider radiative eigen states of plasmon excitations in cavity structures "ATR prism — gap — metal", "vacuum — dielectric film — metal substrate" and in "ATR prism — gap — dielectric film — metal substrate" structure.

We have analyzed the IR reflectivity spectra of micrometric SiC deposited on Si substrates by the CVD technique under different growth conditions. We show that the roughness at the SiC/Si interface gives rise to a damping of the interference fringes above the reststrahlen band without introducing any change of the mean value of the optical response which shows to be dispersionless. On the opposite, roughness at the SiC surface manifests through a falling of the reflectivity on the LO side of the reststrahlen band with respect to the TO one side, and a damping of the interference fringes together with a progressive decrease of the reflectance with increasing IR frequencies. These effects give account for most of the deviations from the optical response associated to the specular reflectance of flat surfaces in SiC/Si heterostructures with a low level of free carriers concentration.

An optical hysteresis and nonlinear absorption of the microsecond and nanosecond laser pulse at interband excitation of different a-Si:H and a-SiC:H films are reported. To explain the experimental results a new physical model is suggested, taking into account the light interaction with nonequilibrium localized lattice vibrations anharmonically coupled with the extended phonons.

Luminescence of CdS nanoclusters in type Y (FAU) zeolite is studied within 10 K - 293 K temperature range under excitation by third harmonic of Q-switched Nd:YAG laser. The exceptional features are revealed in comparison with bulk CdS crystals: essential short- wavelength shift of emission apparently due to quantum confinement and peculiar non- monotonic dependence of the overall emission intensity on temperature.

It is shown that the air-film material reflectance coefficient, and that for the film material- substrate, can be restored from envelopes of the interference pattern in reflectance spectra. Doing so for oblique incidence of light and for two of its polarizations, optical parameters of an absorbing film may be determined without any film dispersion assumptions. Film thickness h is calculated then analytically. Knowing h, the film absorption coefficient can be obtained with high accuracy. Numerical calculations are given to illustrate the method application.

The effect of mean coordination number r on the optical absorption in the region of exponential tail and on the thermal expansion of chalcogenide glasses As-S-Ge are presented. Several important parameters such as optical gap, disorder energy, coefficient of the temperature expansion and their variation with composition have been found. These parameters are shown to be strongly influenced by average coordination number, especially in the region of topological transitions. It is significant that all these parameters exhibit maximums at r approximately equal to 2.7. The explanation is put forward in light of a model which predicts the transformation of the glassy network from two- to three- dimensional configuration at r approximately equal to 2.7. The correlation between optical gap (i.e. intrinsic absorption) and thermal expansion of the glasses shows the possibilities of absorption spectroscopy for testing the properties of non-crystalline materials including the thermo-mechanical ones.

In this paper the light reflection coefficient of the ferromagnetic semiconductor with superlattice is calculated. It is shown that the presence of superlattice will lead to the modulation of the light absorption coefficient of the ferromagnetic semiconductor. It is shown that on the basis of the ferromagnetic semiconductor with superlattice will be developing new methods of optical diagnostics materials for the opto- and quantum electronics.

Photoacoustic and photoluminescence studies on CdS_1-xSe_x nanocrystals grown in a transparent borosilicate glass matrix are reported. Our analysis points out the important role played by the Coulomb interaction in quantum dots whose radii range around the exciton Bohr radius: (1) strong polar coupling to the lattice; (2) observation of optical transitions with different radial quantum numbers in photoacoustic spectra. Photoacoustic spectroscopy has allowed the direct observation of several low and high index states. The experimental results have been shown to be in good agreement with the effective mass- approximation calculations in which the strain effects, due to the hydrostatic compression of the glass matrix on semiconductor nanocrystals, and size dependent dielectric constant have been taken into account.

Contactless techniques of infrared and microwave absorption by free carriers for simultaneous determination of the set of recombination parameters by reconcilable experimental measurements and computer simulation are presented. Variations of recombination parameters induced by technological processes in silicon wafers are discussed.

A computational method of determining spectral dependencies of optical constants, the refractive index n and the extinction coefficient k, for a thin film on a relatively thick and transparent substrate from measured reflectance and transmittance spectra is presented. While the reflectance R and transmittance T are single-valued functions of n and k, the optical constants are multivalued functions of R and T. Thus over a reasonable area of n-k space there is a number of (n, k) solutions for each measured reflectance-transmittance pair. To find solutions the Newton-Raphson numerical method is used. It is easy to find the (unphysical) solutions for low values of n and then we go step by step along the curve n (as a function of k) to the acceptable physical solution. In this way we avoid the possible jump to the solutions which are due to interferences. From time to time it happens that the starting coordinates are not good estimates of solutions and the numerical method failed. In such cases we use some variation of Monte Carlo method, when acceptable starting coordinates are found by chance in a small neighborhood of the original supposed starting point. The solutions are calculated for all measured frequencies. In order to simulate the role of the finite spectral resolution of the apparatus we smooth n and k by averaging their values at central point and its neighbors, with a reasonable step through the simulated spectral width. The method is applied to the semiconducting (beta) -iron disilicide film on silicon substrate.

A theoretical analysis is given of the surface recombination effect on laser generation of longitudinal acoustic pulses in piezocrystals. The acoustic pulses are excited through the inverse piezoelectric effect as a result of the electric fields induced by the spatial separation of photogenerated electrons and holes. Two regimes of dynamics of nonequilibrium electron-hole plasma are considered: the regime of independent motion of opposite-sign charge carriers and one of their ambipolar diffusion. The possibility of generating acoustic pulses with a duration equal to the surface recombination time is predicted. It is shown that the profile of pulse of longitudinal strain is essentially transformed as the surface recombination rate increases. Being based on these facts, a new photoacoustic mean is suggested to determine the high surface recombination velocity (s approximately equals 10⁶ cm/s) in piezocrystals.

EMA model is now used for determination of the components concentrations in heterogeneous materials, prepared as thin (about 1 mkm) films. We can obtain dielectrical function of composite medium (which contain N components) from transmittance and reflectance measurements of the film-substrate system (in the investigated photon energy $HBAR(omega) range substrate must be transparent).

Diffusion length (L) is one of the major parameters of semiconductor materials and can serve as an objective criterion of their quality. It stipulated the necessity of improvement of existing and development of new experimental methods of determination of the diffusion length. Especially in actuality when such a task is presented for disordered semiconductor materials, which are formed in nonequilibrium conditions, and, strictly speaking, electrophysical characteristics of each prepared sample are unique.

The article sets out to investigate spatial-time and spectral characteristics of laser erosive vapor-plasma torch (EVT), formed at the vaporization of mercury chalcogenines targets. Its influence on the synthesis processes of HgTe and CdHgTe layers, condensed in mercury vapor, is described. It is shown that the laser radiation flux density and Hg vapor pressure in the reaction chamber are dominating factors which determine the character of gas-dynamic spread and EVT composition of mercury chalcogenides targets.

A theory of TM type surface polaritons in semiconductor films possessing depletion transition layer, in which electron concentration changes according to the law of hyperbolic cosine, was built. The influence of dissipative as well as non-dissipative damping, caused by plasma resonance in transition layer, on dispersion properties of normal and tangential modes of surface polaritons was determined. It was shown that in the absence of dissipative damping two dispersion branches both for normal and tangential modes of surface polaritons exist, parted by a frequency gap. Taking into consideration dissipative damping leads to vanishing of the gap and existence of only one dispersion branch both for normal and tangential modes of surface polaritons. The damping of tangential mode therewith exceeds considerably the damping of normal mode.

The method of calculation of the fundamental absorption index spectrum k(E) of crystalline dielectrics on the basis of refractive index spectrum n(E₀) in the range of transparency by solving the Kramers-Kronig integral equation has been worked out. Limited experimental precision of refractive index measurements, (delta) n/n equals 10^-4, permits us to obtain low-structuralized (smoothed) k(E) spectra. The method was applied to the ferroelectrical triglycine sulphate crystal. The refractive index dispersion of this crystal reveals the interaction of elementary oscillators. The temperature dependence of characteristic parameter of this interaction was studied in the region including the phase transition (T_c equals 49 degrees Celsius).

Both surface molecules concentration Ns and polarizability Am can be determined from the surface plasmon experiment instead of effective layer thickness, which is usually determined. The new method of quantitative comparison of experimental and calculated surface plasmon resonance (SPR) curves is proposed. Mathematical minimization of curves difference is used in this case. It is shown, that it is possible to determine both Am and Nm from one measurement for accurate experiment and high quality optical system.

The law of the light refraction and analogues of Fresnel's formulas, obtained from the Maxwell boundary conditions, were used to account for the optical parameters of semiconductors. The calculations, based on our formulas and experimental data on reflectivity at normal incident light of Ge, Si, GaAs, CdS in the region of band-to-band transitions are given. The difficulties which took place earlier in optics of highly absorbing media, disappear in our approach: (1) the angle of refraction is a real value; (2) a real part of dielectric function (epsilon) ₁ greater than or equal to 0, because (chi) is less than or equal to n; (3) the index of refraction n is greater than 1.

The structure and optical properties of nickel and palladium-films on crystalline lithium niobate were studied with the help of an electron microscope, an infrared spectrometer, and an ellipsometer. The optical properties of two-layer systems: ion-implanted metal film (10 - 50 nm thick) pyroelectric (crystalline lithium niobate 0.2 mm thick with the spontaneous polarization vector perpendicular to the surface) were studied by measuring the reflectivity in the wavelength region of 0.7 - 15 micrometers. The systems were argon-ion-implanted with ion energies from 50 to 500 keV. The absorbed irradiation dose varied from 10¹⁵ to 5 (DOT) 10¹⁷ ion/cm². After bombarding the surfaces of the nickel-film-systems, the reflectivity almost has not changed over the entire wavelength range, although certain selectivity disappeared, which was due to agitation of the film-pyroelectric interface. We found a striking implantation effect on palladium films, which consisted in abrupt decrease in the reflectivity and in disappearance of the selectivity in a rather wide spectral region of 1 - 15.1 micrometers. The described effect depends considerably on the energy, absorbed dose, and the film thickness. Electron microscopic and elipsometric studies show that the cause of the described effects lay in different changes in both the structure of the near-surface layers and the state of the palladium and nickel film surfaces.

The features of the infrared reflection spectroscopy are considered for long-period semiconductor superlattices. Taking the GaAs/GaP_xAs_1-x superlattice system as an example, the applicability of the bulk model is related to light penetration/localization depths. We propose to use relative measurements (i.e. to study R_pR_s spectra) for raising the accuracy of determination of superlattice parameters by solving the inverse problem.

We analyze potentialities of the surface plasmon resonance (SPR) when investigating thin transition layers at the outer, as well as inner, boundaries of the high conductance metal film on a glass substrate. Using the objective function, one can determine, with high accuracy, more than three optical parameters of the SPR supporting two-layer metal film. The data obtained by our method for the Mn:Ag two-layer system are compared with those given by the traditional quartz microbalance method. A good agreement is found between the two sets of thickness and refractive index values for both layers.

Interactive graphic system 'ELLA' is described which is an integrated program packet for reverse problem solution in ellipsometry. The solutions stable to experimental errors are found by two algorithms: a simplex method under constraints and a regularizing iteration method. A developed graphic procedure kit includes display of graphic surface layers, their optical parameters, and all main results of intermediate calculations. Specialized graphic input functions allow us to change the parameters of a chosen solution method, the basic data, to enter new additional information, etc. On the examples of model structure of GaAs-oxide MAI capabilities in ellipsometry for determination of multilayer structure optical parameters are studied.

Excitonic spectra of ternary compounds RbAg₄I₅ and Me₂AgI₃ (Me: K, Rb, Cs) are studied. The exciton binding energy Rex and band gap Eg were determined. For the Me₂AgI₃ the one-dimensional character of excitons was established. The temperature dependence of low-frequency exciton absorption bands parameters was studied in 80 - 300 K interval.

The authors developed the methodology for optical property investigation of thin films of high and low absorbing substances on transparent and opaque substrates by means of spectroellipsometry with excitation of surface polaritons. For thin films of low absorbing substances on opaque substrates we used Beattie ellipsometric method with excitation of surface polaritons according to Otto scheme, and for the films of high absorbing substances on transparent substrates we used the same Beattie method with excitation of surface polaritons according to Kretschmann scheme. Measurements of ellipsometric parameters of several angles of incidence gave the possibility to use the solution of inverse ellipsometry task by means of electronic computer and to determine optical constants of thin films, their thicknesses, and optical constants of substrates in the case of high absorbing metal substrates. Obtained results of spectral relations of optical constants either for massive aluminum or for thin aluminum films gave us possibility to draw some interesting conclusions of their electron structure. In addition, they gave an opportunity to observe experimentally the separation of optical conductivity bands caused by electron transition in K and W points of Brillouin zone.

Using IR spectroscopy, Rutherford back-scattering technique and optical microscopy the structure of SIPOS films produced by CVD method is investigated. The network of oxygen- doped silicon is shown to represent a mixture of Si-O_y-Si_4-y complexes with 0 less than or equal to y less than or equal to 4 and micro-inclusions of strongly oxidized silicon. Contribution of these complexes is dependent on the processes of layer growth and post- treatments. IR spectroscopy was demonstrated to be a convenient technique for determination of oxygen concentration and structural arrangement in silicon-oxygen phase.

The new method for the determination of the high absorptive thin film parameters is proposed. This technique consists in the complex ellipsometry plus photometry measurements. The comparison of the principal parameters of the proposed technique and the traditional ellipsometry methods is carried out.

Intra cavity laser spectroscopy which is effective and simple in creation has been proposed and studied. The method may be used in systems where the longitudinal relaxation time is considerably greater than the pump pulse duration. It is based on the possibility both of essential increase of the laser pulse duration and of its control over a large range. In the experiments with Al₂O₃:Ti³⁺ laser the additional increase in sensitivity was equal to 10² - 10³ as compared with conventional absorption spectroscopy. The sensitivity control interval was equal to 10^-5 - 10^-6 sm^-1. The basic peculiarity of the proposed method is the application of the special receiver signal processing for the elimination of the influence of the laser pulse energy (duration) high fluctuations.

In the present work processes of photolysis and photochemical transformations in crystals, thin films, and heterogeneous environments of layer cadmium, lead, and zinc halides have been investigated. It has been found that photolysis takes place in these materials at excitation of electron-hole couples. Excessive metal atoms serve as photodecay centers. Photolysis kinetics are determined by halogen diffusion. Products of photolysis are metallic and partly oxide phases. The maximal photolysis degree is determined by the critical size of metallic inclusions. It has been shown that copper impurity leads to photochemical reactions (PCR) in cadmium halides. PCR in CdI₂ - Cu crystals is caused by photothermal decay of copper- intrinsic defect complexes. In CdBr₂ - Cu PCR takes place as a result of copper impurity photoionization, and in CdCl₂ - Cu it is a result of recharging Cu⁺ yields Cu²⁺.

HTSC structures based on epitaxial YBCO films subjected to He-Ne laser irradiation have been studied. Two- and three-dimensional images of local resistive regions have been obtained. These give an opportunity to analyze the homogeneity of HTSC films.

In the present report, dealing with a media in which the spatial dispersion (SD) is essential, it is shown: (1) what discrepancy one can observe between calculated and measured data if the Kramers-Kronig relations, derived for local response for perturbation, are used. (2) that these relations are true if one uses them for certain 'effective' values of optical constants of Pekar's theory, so for the certain theory parameters and not for real medium characteristics.

Peculiarities of thermal dynamic gratings application for heat transfer study of solids are investigated both theoretically and experimentally. Techniques are proposed for the reduction of influence of thermal grating aperture limitation and scattered coherent background on accuracy of measurements. A thermal excitation of transparent samples with absorbing film of liquid in contact is considered.

In this paper, we present numerical simulation results of spatially modulated carrier transport and of non-linear optical phenomena for the case of non-uniform electron gas heating as well as the experimental data on light self-diffraction efficiency in external microwave fields. The expected field induced variations of refractive index modulation seen in light self-diffraction on transient gratings are determined mainly by electro-optical non-linearity due to enhanced internal field.

The simple nondestructive method for reconstruction of the refractive index distribution in the waveguide cross section is presented. Sample surface immersing and the interferometric method of registration are utilized in this technique.

Results of the experimental investigations of absorption of laser pulses in amorphous (a-) and crystalline (c-) As₂S₃ films are presented. The optical transmission hysteresis and reversible film photodarkening at interband excitation of a-As₂S₃ films in a blue-green spectral region are reported. It was suggested that the nonlinear light absorption could be explained by taking into account the light interaction with nonequilibrium localized lattice vibrations anharmonically coupled with the extended phonons. The measurements of peculiarities of the pulse absorption in crystalline As₂S₃ films can confirm the proposed explanation.

We demonstrate for the first time the applicability of transient grating technique to study carrier dynamics in porous silicon and to characterize the sublayers with the different structure in an optical way. The parameters of deeper layers of 130 mm thick porous Si structure have been found similar to those in crystalline substrate. The free standing films at high injection levels indicated very fast nonequilibrium carrier recombination with t equals 430 ps, while the carrier lifetime in its crystalline substrate was above 2 ns.

The possibility to combine photorefractive effect and metastability of defect states in GaAs crystals is combined. Peculiarities of free carrier and photorefractive nonlinearities at conditions of deep donor EL2 optical quenching by short laser pulse are analyzed theoretically and experimentally. The enhancement of low temperature photorefractive effect was observed at T less than or equal to 250 K in a good agreement with theoretical simulation and attributed to the temporary EL2 quenching by nanosecond pulses.

The feasibility of the optical scheme of measurement of concentration of nonequilibrium charge carriers has been demonstrated. Relaxation of electrons and heating of sample have been taken into account dealing with theoretical description. Experimental research has been carried out with c-Si sample.

An interferometric technique of a position and beating control for an axial rotating body position is described in this paper. A Michelson interferometer without a signal spectrum transfer in a high-frequency range is used as a position and beating sensor of a rotating body. An autocollimator as a reflector insensible to angular rotating is used in a measuring level of the interferometer. The autocollimator is tightly connected with a cylindrical information carrier by a magnet lock for motion dynamics investigations. It is found that the position error of the proposed position sensor does not exceed (lambda) /8.

An optical interference method for simultaneous determination of the temperature dependences of refractive index n(T) and thickness 1(T) of transparent parallel-plane samples has been worked out. The method has been applied to a glass plate sample, and it was shown that dn/dT and (d1/dT)/1) temperature derivatives satisfactorily correlate with corresponding reference data. The determined inaccuracies of temperature changes of (delta) n/n and (delta) 1/1 have not exceeded 10^-4. Investigation of (NH₄)₂SbF₅ crystal by the proposed optical-interference method has confirmed the occurrence of the second order phase transitions at 292 and 168 K.

The dependencies of linear losses coefficient (alpha) , two-photon absorption constant (beta) , optical damage threshold I_p and pseudogap width E₀ on structure and concentration changes of glasses from the glass-forming region of Ge-As-S system along the As-GeS₂, As-Ge₂S₃, As₂S₃-GeS₂ and As₂S₃-Ge₂S₃ sections have been experimentally studied. The critical values of concentration and average coordination number at which the (alpha) , (beta) , and I_p reach their extremes were determined. These results have been discussed in terms of phase and structure-topological transitions.

Several different schemes of four wave mixing (FWM) in resonant media, particularly, using ionized atomic or molecular vapor states, are considered. It is shown that the most efficient process can be achieved with FWM scheme using the ion grating. In this case spatial mismatch between recording interference pattern and light induced grating can be provided, when external electric field is applied to recording non-linear medium.

The investigation and utilization of noncritical phase matchings in optical devices is a new focus for bulk and integrated nonlinear optics research. The use of vectorial group and multiple noncritical phase matchings for the sum- and difference-frequency generation in nonlinear crystals permits both to extend essentially the tuning range of the wide-band conversion to cover practically the entire transparency region of a crystal and attain the bandwidth of conversion of the order of 10³ cm^-1 in the mid-IR and the near-IR spectral region. We discuss here possible applications of noncritical phase matchings.

On the basis of experimental investigations of authors the expediency of using photoluminescence (PL) method in gallium arsenide semiconductor device technology is shown.

Another pronounced anomaly of the fundamental properties of photoexcited porous silicon samples is reported -- namely, giant efficiency of sound photogeneration under the irradiation of nanosecond laser pulses. The origin of this anomaly is discussed. The good prospects are demonstrated of techniques based on photoacoustic effect for the studies of fundamental properties of porous Si, in particular, reconstruction of fundamental absorption edge with the option of in-depth profiling, description of the kinetic properties of carriers responsible for the emergence of red-orange emission band, reconstruction of the spectrum of non-radiative transitions.

The characteristics of injection laser with recombination region based on (In,Ga)As quantum dots have been studied. The quality of the structures does not prevent the specific features of quantum dot active region to manifest itself in laser characteristics. The single-mode lasing has been reproducibly achieved in broad area laser diodes. The threshold current densities have been found to be higher than the theoretical values due to non-radiative recombination. The results obtained are promising for applications where a very narrow lasing spectrum is important, i.e., laser arrays, pumping of solid-state lasers, etc.

Unique polarization properties of the exciton luminescence in semiconductor superlattices (SL) are the subject of a great current interest. Polarization effects in SLs may be caused by different mechanisms, such as formation of twodimensional subbands, exciton localization, existence ofthe microreliefat heterointerfaces, etc. [1-3]. We have investigated the polarization properties ofthe photoluxriinescence (PL) spectra of GaAs-AlAs superlatlices in a wide range ofquantum well and barrier widths. The sample parameters, i.e. well width d, the barrier width d, the number ofperiods N, the type of SL, and the corresponding degrees oflinear polarization are listed in table 1. In both direct-gap SLs-I (d <4 n.tn) and indirect-gap SLs-II (d <4 nm) the polarization of PL lines is caused by the splitting of heavy and light hole bands and the anisotropy ofheavy holes, but this effect alone cannot explain the polarization ofthe luminescence irradiated in the direction normal to the surface of investigated structure (i.e. at small detection angles). For SLs-I we have observed rather large linear polarization PL=(I-I)/(I.,+IS), where I and I are the intensifies of exciton luminescence polarized in the plane ofdetection and normal to it. In this case polanzation may achieve values ofabout 20%. In SLs-II with narrow wells photoluminescence is caused by indirect exciton transitions between X-electrons of AlAs and r -heavy holes of GaAs. It is known that such excitons are localized at interface inhomogeneities [4]. The value of P1 for these SLs is lower than for the SLs-I (L=5-1° %). We have studied the dependence ofpolarization degree on the angle of PL detection for SL—II with the well width 3.4 run and barrier width 4.0 nm for two cases of crystallographic directions ([1 10] and [1 1 0]). The parameters of such samples were close to the case when direct —indirect crossover is observed. As a consequence of this fact two lines were observed in PL spectrum, one of which is associated with indirect recombination of X-electrons and another with direct recombination of F-electrons. r-Iine is almost unpolarized (L'1)' while X-line is characterized by rather large polarization degree (up to 10%), which decreases with the increase ofdetection angle and changes its sign (for small detection angles) with the 90°-turn of the sample around the axis normal to its surface. This anomalous behavior requires an adequate theoretical explanation. From our point ofview such explanation may be given if the existence of heterointerface corrugations in superlattice is taken into account. At the same time the fact ofsmall broadening of observed PL line (substantially lower than possible line splitting due to monolayer fluctuations in quantum well width) proves a strong correlation between such corrugations on both sides ofeach quantum well, i.e. the shape of corrugations in heterointerfaces in superlattice is determined by the shape of corrugations on the surface ofthe substrate.

The determination of life times from experimental data of luminescence decay curves (being represented as a sum of a some number of the exponent function with unknown weight factors and often with unknown error of measurement), was and now remains important for time resolved spectroscopy of complicated bio-organic molecules and complexes. Standard approximation procedures (the method of least squares, Laplace transform) used for this purpose does not always permit us to receive the unequivocal 'spectrum' of exponent. The recently proposed maximum entropy method requires the additional data about anisotropy of molecule polarizability and its relaxation, the energy population of investigated molecules on various degrees of freedom, etc. Therefore development of alternate techniques of expansion of the experimental decay curve from exponential sum is important.

Photoluminescence (PL) and Fourier transform infrared spectroscopy (FTIR) have been used to characterize porous silicon layers (PSL) exposed to HF destructive etching. The results obtained lend support to the view that chemical passivation, in particular by oxygen, is the major factor which controls the origin of PL. The PL intensity and the PL shift are ascribed to the changes in hydrogen and oxygen termination of pores.

Mechanisms of macrodefect's and isovalent admixture's influence on photoluminescence spectra and halvanomagnetic parameters of HgCdTe/CdTe heterostructures were investigated. Profiles of electrical and structural parameter distributions through the depth of epilayers HgCdTe (x approximately equal to 0.2, p-type and with mixed conductivity), on CdTe substrates ('clean' and with 4% of Se or Zn components) were measured. There was detected substantial increase of well-known in CdTe donor-acceptor photoluminescence band 1.43 eV (T equals 77 K) in transition layers and CdTe substrates with increased macrodefect concentration (dislocations, subgrain boundaries, Te precipitates). It was established that such elevation was dealing with the donor component of conductivity in substrates and corresponding epilayers. The donor's nature was dealing with the substrate's defect structure. So photoluminescence band intensity may characterize CdTe defect level and permit us to reject such substrates.

Some characteristic features of the formation of ultrashort lasing pulses in InGaAsP/InP lasers led to the idea of the existence of short peaks of coherent radiation below lasing threshold. A sensitive autocorrelator set up based on two-photon absorption was optimized to study superradiation in semiconductor materials. Sensitivity threshold as low as 50 mkW was achieved for radiation with 1.3 mkm wavelength. Autocorrelation functions of superradiation for InGaAsP/InP cw laser at 0.8, 1.0, and 1.9 of threshold current were obtained and prove an existence of some ultrashort pulses below the lasing threshold. These pulses exist even at superluminescent regime, which occurs at a pumping current density of 1700 A/cm². It corresponds to about 500,000 carriers in the cube with dimensions equal to the wavelength of emitted radiation (1.28 mkm in semiconductor material). This effect may be caused by collective irradiation phenomena similar to known Dicke superradiation in solid state lasers.

We have demonstrated the capability and limitation of nondestructive photoluminescence and x-ray diffraction techniques in the characterization of GaAs, AlGaAs, InGaAs matched epitaxial layers grown by molecular beam epitaxy as well as quantum wells grown by metalorganic chemical vapor deposition. The application of the x ray diffraction and the photoluminescence methods to the same objects made it possible to control Al content in the Al_xGa_1-xAs layers in the range of x (0 less than or equal to x less than or equal to 1) and to solve some technological questions connected with layers lateral homogeneity.

We have studied the stability of the visible photoluminescence (PL) in the stain etched porous silicon (PS) prepared with the help of laser irradiation. The observation of PL evolution from this PS under exposure to ambient air is reported. We find the displacement of the PL intensity peak of the steady-state spectrum from 'green' to 'red' spectral range, (lambda) - integral PL intensity increasing by 50 - 80% during 15 - 30 min. under air exposure. With increase of exposure time during several weeks to air the average relaxation time of the slow component of PL decay increases and the spectra dependence of this time remains exponential. Possible explanation for the observed PL evolution includes processes related to water evaporation, to replacing the unstable H-passivated surface with the more stable O-passivated surface, to decrease the number of the Si dangling bonds, and to increase the oxide barrier which greatly reduces the carrier tunneling from light emitting nanocrystallites. The results can account for the import role of the inner surface chemistry in recombination within the framework of quantum size model of the PL. The change in PL is inferred to be associated with the interaction between as-grown PS and ambient air, so PL controls as-grown PS-air interaction.

Results on creation of thin-film single-crystal high-resolution screens with energy control of luminescence color are presented. In order to create phosphor films ion-plasma technology for deposition of yttrium and lanthanum oxides and oxysulfides activated by rare earth elements has been developed. The screen consists of phosphor film on phosphor substrate with different colors of luminescence (e.g. Y₂O₃-Eu film with red color on Y₃Al₅O₁₂- Tb, Ce substrate with green color of luminescence). Electron irradiation causes luminescence with color that depends on energy of the electron beam. The physical reason for color change is that electron beam energy defines electron penetration depth. If the energy is weak, only the film is excited. More powerful beam penetrates into the substrate and thus changes the color of luminescence.

The spectra of photo- and x rays-luminescence of cadmium tungstate monocrystals with the impurities of heavy (Pb²⁺, Bi³⁺) and rare-earth ions (Pr³⁺, Sm³⁺) were investigated. The main spectral and kinetic characteristics of the photoluminescence are given, which can be the evidence of the presence of impurities in the cadmium tungstate crystals.

The luminescence and excitation spectra and kinetics of luminescence decay of alcaline metal and calcium chromate crystals and mixed crystals of the cesium chromate with the CaCrO₄ and CaCl₂ impurities were investigated. The influence of the thermal treatment temperature and impurity implantation on the luminescent properties of these luminophors has been examined. Three types of the complex centers of luminescence were found, and their spectral-kinetic characteristics such as a relative quantum efficiency, decay time of the luminescence, and conditions of formation were obtained.

The experimental method for express diagnostics of luminescence intensity distribution (and, hence, of distribution of radiative recombination centers) over the semiconductor wafer surface is described. The method is based on transferring the TV image of the luminescent surface of a semiconductor wafer to the oscilloscope screen in axonometric projection. It makes it possible to measure both the relative efficiency of luminescence in different points of the wafer surface and also the absolute values of this efficiency. An example of the use of the method developed for a wide-band-gap II-YI semiconductor (cadmium sulphide) is presented.

A study of facet degradation of InGaAs quantum well lasers is reported. We tune up a Raman and photoluminescence micro-probe technique for determining the crystal structure and the temperature profile of the cladding layer, in steps of approximately 1 micrometer, with a temperature resolution better than 1 degree Kelvin. The cladding layer composition and cross- section temperature profile have been monitored during operation. A clear correlation between the facet degradation and the type of protective coating is found.

An anomalously high efficiency of sound photogeneration in the ensemble of spatially separated CdS microcrystals embedded in zeolite cavities and excited by nsec laser pulses is found. A qualitative explanation of the observed effect is made. The photoacoustic spectra of such specimens which were obtained by gas-microphone detection call made it possible to reconstruct the fundamental absorption edge of CdS microcrystals in the (alpha) less than 10³cm^-1 region. The presented results reflect the efficiency of the absorbed- to-thermal energy conversion.

In this paper a complex diagnostic of impurities defects interaction as a result of irradiation by a ruby laser pulse of 20 ns duration has been made. Photoluminescence, photoconductivity, Raman scattering, microscopic and electrophysical methods were used to characterize the deviation from the stoichiometric composition, impurities activation and disactivation, tellurium layer and dislocations network creation. The mechanism of dislocations appearance as shown is mechanical stresses accumulated in laser irradiated area under the threshold of plasticity of the material.

The results of light scattering and photoluminescence investigations of sub micron free- standing silicon crystals are presented. Measurements were carried out within the wavelength range 0.2 - 1.5 micrometer. It was found that if the size of micro crystals is less than 1 micrometer, the peak of (L₃ - L'₃)-transition in the absorption spectrum shifts towards larger photon energies. We have found also that the micro crystals are the strongly depolarizing medium, and the depolarization depends on wavelength and angle of observation. Moreover, s- and p-polarized scattered light spectral dependences are different. The photoluminescence spectra of the crystals of micron and submicron scale are essentially different from the conventional bulk silicon spectra. At 4.2 K temperature we have observed new visible and several infra-red photoluminescence bands. While at room temperature only visible light band was found. The results obtained are treated using the Mie's theory and the suggestion of the surface atomic layers reconstruction.

The complex method for determination of the important parameters of narrow-gap semiconductors and devices on their base at room and higher temperatures from the analysis of field and temperature dependences of the negative luminescence phenomenon has been developed. The study of the lifetime, surface recombination velocity and composition of narrow-gap epitaxial Hg_1-xCd_xTe films has been reported.

The luminescence intensity of porous silicon layers (PSLs) is investigated as a function of their thickness and temperature. For thin PSLs the emission intensity was found to depend superlinearly on thickness and exponentially on temperature. For thick PSLs no rise in emission intensity with lowering temperature is observed. The data obtained suggest that at room and some lower temperatures the photocreated excitons are free to diffuse in PSL and can be rejected into the silicon substrate. This behavior may also explain some recent experimental results. Also in the present work we report on results of combined PL and capacitance measurements which show that, for PSLs formed at small current densities, the distance between pore centers is, within the experimental uncertainties, the same as that between fluorine ions in the Helmholtz layer. This allows us to conclude that in the region of weak anodic polarizations every fluorine ion gives rise to the growth of individual pore.

We experimentally established that the dependence of ratio between luminescence intensities of two centers on excitation power was determined by, besides the concentrations of these centers, the inverse ratio of their radiative lifetimes. This effect can be used to measure a power of laser excitation by relationship of luminescence intensities, corresponding to two centers with different radiative lifetime. We propose the kinetic model to explain the various relationships between luminescence intensity and excitation power (such as linear, superlinear, and sublinear). These relationships are plotted for a material with two radiative centers and a nonradiative one.

A novel time-resolved nonlinear spectroscopic technique is described, which is based on stroboscopic registration of optical polarization transformation taking place at a vector incoherent two-wave mixing interaction in a modified Mach-Zehnder interferometer. It allows an accurate measuring of the dynamics of excitation and relaxation for real and imaginary parts of complex nonlinearity tensor components. The technique is demonstrated for measuring the light-induced change of transient absorption (delta) (alpha) _e(t), (delta) (alpha) _o(t) and refraction (delta) n_e(t), (delta) n_o(t) for bacteriorhodopsin- based film pumped by linearly polarized laser pulses.

Two GaAs/AlGaAs passive semiconductor channel waveguides of the multiple quantum well structure have been made by molecular beam epitaxial growth technique. The specimens were studied by photoreflectance (PR) spectroscopy at room temperature. The micro-structures of the PR spectral energy features on the layers of the multiple quantum wells and band edge transition were observed. The optical transition energy features were fitted by the first derivative Gaussian function form (GFF) and the peak positions of the theoretical prediction for the micro-structures were calculated by using effective mass envelope function model. The energy features of the micro-structure in PR spectra were identified and interpreted. The results show that PR is a powerful tool to characterize the optical waveguides of multiple quantum well structure.

Photoreflectance spectra of InGaAs/GaAs single quantum well structures are studied at pump power densities from 0.5 to 300 mW/cm². The spectra measured at different pump powers were found to differ not only in amplitude but also in spectral position. Moreover, a linear correlation between the amplitude and the spectral position of the modulation spectra takes place. We explain this dependence by means of the conventional scheme of modulation spectra modeling, taking into account the second order expansion of the quantum well refraction and absorption indices with respect to the excitonic resonance frequency. Plotting spectral positions of modulation spectra features versus modulation spectra amplitudes we can find the spectral position limit when the amplitude tends to zero. This limit is an excitonic resonance frequency in the absence of perturbation induced by pumping light. We have found that the observed spectral displacement of the modulation spectrum with respect to the nonperturbated excitonic frequency is equal to a half of the excitonic frequency shift induced by external modulation. Using the pumping-induced excitonic frequency shift, derivatives (delta) R/(delta) n and (delta) R/(delta) k, and modulation spectrum (Delta) R/R itself, it is easy to find the absolute value of the excitonic absorption (the excitonic oscillator strength) in a quantum well.

In the framework of virtual crystal approximation using the empirical pseudopotential theory optical transitions of Si_1-XGe_X have been calculated. The effects of hydrostatic and uniaxial stress, and alloy stoichiometry on the optical gaps were investigated. Optical constant spectra for the Si_1-XGe_X alloys of different content have been measured by spectroscopic ellipsometer. Strain relaxation in annealed Si_1-XGe_X layers has been observed. From the comparison of measured direct optical transition energy E1 with the calculated one the value of lattice deformation in the pseudomorphic Si_1-XGe_X layer has been determined. Since the mechanical stress and material composition affect the distinctive behavior of different optical transitions it allows us to put forward a spectral measurement technique for determination of crystal lattice strain and alloy parameter X simultaneously.

We present an algorithm and results of calculation of the binding energy and the oscillator strength of an exciton in a GaAs/InGaAs/GaAs single strained quantum well taking into account self consistency effects and phase space filling. We assume that the well is placed in a depletion region and the well filling by free carriers is governed by a surface voltage. The wave functions of the charge carriers motion in the direction transverse to the well plane were calculated via self-consistent solution of Schreodinger and Poisson equations. The exciton binding energy, wave functions of in-plane motion and oscillator strength were found by a variational approach. The variational function of the exciton was chosen in the form that explicitly includes the phase space filling. It is found that the dependence of the binding energy and oscillator strength of the exciton versus the surface voltage is not monotonic. This is explained by a competition of the self consistency effects and the phase space filling.

We have studied the processes of modulation of infrared radiation when surface plasmon- polaritons and guided wave plasmon-polaritons are generated by the attenuated total reflectance at surfaces and in thin films of semiconductors. For these processes a comparison analysis of their characteristics was made when charge carrier concentration changed due to interaction of modulated radiation with the sample surface and bulk. It is shown how these characteristics are modified due to surface interaction.

Raman studies of Si layers prepared on c-Si and Al₂O₃ substrates at 300 K by well defined cluster beams have been carried out to establish correlation between the cluster species and the layer composition. The Si clusters were generated by a carbon-dioxide-laser-induced decomposition of SiH₄ in a flow reactor and were transferred to a free molecular flow by introducing a skimmer into the reaction zone. A mass spectroscopic analysis shows that this source emits two qualitatively different types of clusters: small clusters consisting of up to 12 atoms and large species of nearly 10³ atoms. To produce the Si layers the substrate was placed perpendicular to the cluster beam. The Raman spectra of the deposited clusters show a broad amorphous-like band and a relatively sharp peak at 518.1 cm^-1. Analysis of the Raman shift and line width of this peak based on phonon confinement models allows us to conclude that this peak corresponds to nanocrystals with a size of about 3 nm. This size corresponds to the number of atoms in the large clusters of the cluster beam. It means that the layers conserve the specific properties of the large incident free clusters.

Absorption, photoluminescence, and Raman scattering studies of CdS_xSe_1-x nanocrystals, as a function of the crystallite mean radius, are reported. By properly considering the competing effects of spatial localization and strain, the chemical composition and the lattice contraction are assessed. Two different techniques have been used to analyze the electron-phonon coupling. Photoluminescence and absorption studies allow us to measure the Huang-Rhys parameter. The size dependence of the Frohlich electron-LO phonon interaction has been extracted, for the first time, from the polarization analysis of the Raman scattering. Our results unambiguously show that, in the investigated nanocrystal size range, the electron-phonon coupling monotonically increases at decreasing the nanocrystal radius. The observed behavior is in agreement with the latest calculations.

The facet heating of GaAlAs/GaAs DQW high power laser diodes is one of the main processes for fast degradation and catastrophical optical damage in the near of the laser mirrors. This local heating is caused by nonradiative recombination of the injected carriers and by optical absorption near the cleaved or coated facets. The Stokes and anti-Stokes lines have been measured by excitation with an Ar⁺ ion laser by high local resolution of about approximately 1 micrometer and an accuracy of the beam position of approximately 0.5 micrometer. The facet temperature is calculated from the ratio of Stokes and anti-Stokes intensity. Lateral and transversal temperatures distribution at the facet of multistripe arrays and the temperature as a function of injection current have been studied. The influence of different mechanisms on the accuracy of the obtained temperatures is discussed.

The Raman scattering analysis of damaged and amorphous SiC layers obtained by ion beam processing has been performed as a function of the processing parameters. Two different sets of samples are investigated: (a) 6H-SiC samples implanted with Ge⁺ ions at different doses, and (b) SiC layers obtained by C⁺ ion implantation into amorphous Si. In the first case, damage accumulation and amorphization are analyzed as a function of the implanted dose. In the second case, deep in the analysis of the dependence of recrystallization processes on the amorphous structure, the ion beam induced epitaxial crystallization (IBIEC) of amorphous layers obtained by carbon implantation is also studied. The results show the strong ability of Raman scattering for the identification of amorphous phases in the layers, as well as for the evaluation of residual damage after thermal or IBIEC processes. Correlation of these data with IR, RBS and TEM allows us to determine the structural evolution of the samples under thermal or irradiation processes.

A new method for measurement of bulk temperature in the laser diode active zone using the spectral position of the peak gain is offered. The facet and bulk temperatures of a few diodes with output power from 1 to 10 W are measured. The obtained results allow us to conclude that the main reason for bulk temperature increasing is ohmic heating and that exists temperature gradient between facet and bulk temperatures along the active region length.

A numerical algorithm for calculating the diffraction of plane wave by the one-dimensional binary grating with infinite conductivity and a period smaller than a wavelength is suggested. The algorithm is based on the numerical solution to Maxwell's equation using the Rayleigh expansion. The results of computer-aided simulation are presented.

We present a Kirchhoff-Beckmann approximation of an algorithm for calculating the angular intensity distribution of the light scattered from a microrelief surface of finite conductivity using the algorithm of a fast Fourier transform. Results of computer-aided simulation enables us to establish both the algorithm feasibility limits and a number of relationships connecting characteristics of the scattered light with the diffraction grating parameters.

Raman scattering and photoluminescence in crystals of (beta) -ZnP₂ grown from vapor phase have been investigated at temperatures 1.4 and 1.6 K. The excitance of exciton transitions and exciton-admixture complexes has been found. The energy of 11 types of phonons from 16 to 125 meV have been determined.

In this paper we present Raman results obtained for PbI₂ crystals in the presence of stacking faults for which the effect of confinement of the optical branches is closely seen. We also report the observation of interface phonons by Raman scattering from stacking faults region.

We offer a series of simple method of local testing of inhomogeneities in transparent dielectric crystals, which can be realized using the standard Raman equipment. We demonstrate that these methods are powerful tools of investigation of spatial distribution and kind of defects.

By the methods of Raman spectroscopy and x ray diffraction we studied the short-range order structure of binary and ternary glassy alloys in As(Sb)-S(Se)-I systems. The types of bonds and main structural parameters are defined. On the basis of the obtained results the model of 'microheterogeneous' glass structure was worked out.

An instrument for nondestructive and contactless determination of growth-defect planar distribution across LEC grown GaAs wafers has been developed and assembled. It can be used for monitoring the defectiveness of the wafers as for evaluation of the effect of technological processes (as doping, annealing, irradiation, etc.) on homogeneity of wafer characteristics. The possibilities of the instrument and transient grating technique for metrology of semiconductor parameters are shown.

Laser microscopy offers numerous possibilities for measurement of topographical, electronic, and material properties of microelectronic and optoelectronic devices.

In this paper some experimental results are presented, related to practical applications of holographic nondestructive technique for inspection of museum items condition, especially in detection of deformation, stress analysis, and defects localization. These results are obtained using the basic principles of traditional double-exposure holographic interferometry as well as electronic speckle pattern interferometry with computer image processing. In the latter case the accuracy in displacement measurements was studied on a test-object. Several museum items have been selected for their condition inspection: a 19th century oil painting, an 18th century icon on wooden panel, and an enameled terra-cotta vase of the 17th century. The described technique can give quite accurate meteorological information, and is also rather promising for rapid qualitative analysis of the object condition before and after restoration, as well as during its storage.

One of the main storage elements is a memory element including the light-sensitive medium in which usually takes place the optical information recording. The information recording density on recording media is defined in the first place by their resolution which depends on medium homogeneity and degree of defects presence. Among new materials sensitive to light of particular interest are alkaline-earth sulphide films with additives of rare-earth element ions. Such films allow us to record information with multiple reading and rewriting. The information recording on such media takes place due to electron trapping by trap states materials irradiation with 488 nm laser radiation. The reading takes place owing to release of earlier trapped electrons from long-lived states under action of IR laser radiation (the wavelength is of 1064 nm).

The method of the recording and storage of the information in boron-doped silicon using YAG:Nd laser is proposed. The laser-induced centers, which are generated during the laser annealing of silicon can be used for the recording of information. The dependence of a concentration and a time-stability of generated centers on parameters of the laser radiation and impurities content in the silicon are investigated experimentally. The model of the generation of additional centers in the laser-annealed area is proposed.

Reversible recording medium based on glass/crystalline phase transition was considered. The spatial/temporal distribution of the crystalline phase in radiation zone was studied. Methods of dynamic range expansion while recording and providing of high signal/noise ratio after multiple recording/erasing cycles were considered.

X-ray lithography with synchrotron radiation was applied for formation of the Fresnel zone structure profile onto a curved surface of a refractive polymer lens to achieve multifocus properties of the lens. First prototypes of the hybrid refractive-diffractive lens were fabricated in such a way and their optical properties were investigated. Some possibilities for creation of diffraction apochromatic optical elements are considered as well.

The new synthesis methods of the polarizers and polarizing beam splitters are shown. These methods are based on using the unequal thickness multilayer coatings with symmetrical periods. These enable us to design the polarizer with up to nearly 100% degree of polarization of the transmitted and reflected beams in the spectral bands of 100 - 200 nm and polarizing beam splitters with apertures up to 20 - 25 grade.

Using Jones matrix calculus the main features of the polarization optics of uniaxial absorbing crystals exhibiting linear birefringence, optical activity, and linear dichroism are discussed. Polarization of the eigenwaves that propagate in the crystal unchanged, as well as the azimuth and the ellipticity of the emergent light waves, is analyzed. The crystal optical effects occurring at the isotropic point of uniaxial absorbing crystals are studied in detail. Despite that the dichroism of the eigenwaves is absent and the crystal can be treated as a phase retardation plate, it manifests the absorption dependent on the incident light polarization. It is revealed that singular directions can exist in optically active linearly dichroic uniaxial crystals in which only one, but not two, eigenwave propagates. The propagation along the axial direction of the light wave polarized orthogonally to the eigenwave is considered.

Plastic pipes are frequently used for low pressure gas and water distribution. One of the main problems with their wide commercial applications is rapid crack propagation (RCP). This results in enormous losses of energy resources and environment pollution. Recent incidents show that it is of importance to find criteria to assess the safety conditions for large diameter piping before its installation. In this report some results of holographic non-destructive testing of plastic pipes are presented. Double-pulse holographic interferometry measurements of stress distribution at small scale steady state (S4) tests for 3 - 5 bar pressurized plastic pipes with (phi) 110 mm to 200 mm were performed. Also the mechanically induced vibration modes of non-pressurized (phi) 200 mm plastic pipe were visualized with the purpose to check stress distribution.

The purpose of this paper is the investigation of a photostimulated modification of optical properties of semiconductors subsurface region. The experiments have been carried out on the II-VI (CdS,CdTe) and III-V (GaAs) semiconductor monocrystals. We have shown, that during the photostimulated process the enriching of cadmium is occurring in the subsurface region of CdS monocrystal and thus the complex refractive index is strongly changed. The first time this phenomenon was detected and investigated by us in CdS-single crystal it was named low temperature photohydromodification (LPHM). In this paper LPHM-phenomenon is discovered in GaAs and CdTe crystals. We have theoretically shown that the subsurface region refractive index changes take place due to increasing of clusters concentration, that consist from interstitial atoms, and changing of their forms during LPHM-process.

Using the conventional porous silicon (PS) technology we realize an Si-based irreversible optical recording medium. The recording was performed on PS layers by the second harmonic ((lambda) equals 0.53 micrometer) of YAG-laser operating in the multipulse mode. The results have shown the ablational mechanism of the optical recording.

The cathode ray tube cameras can be used for measurement and visualization of 300 - 2000 degrees Celsius temperature fields that apply in an opto-, micro-, and quantum electronics production. The computer simulation of physical processes in the camera allows us to get necessary information for increasing the temperature accuracy by a digital compensation of the errors. The sequence of the computer simulation and the practical results of temperature measurement are represented.

Some peculiarities of experimental data obtaining procedure being used in dielectric tensor field optical tomography technique are discussed. They concern the problem of coordinate system choice in which measured data for arbitrary analyzing ray have to be presented. We propose to determine for each ray its own coordinate system which axes coincide with azimuths of polarization ellipses of eigenpolarization states. Since any optical system has two eigenpolarization states of waves that propagate in the medium, coordinate systems being related with them are definitely determined and easily reconstructed ones. Normalized Jones matrices (experimentally determined data in our case) can be represented in each ray eigenpolarization coordinate of these systems. Determination of the coordinate systems own mutual orientation provides consideration of all measured data in one of them that is a physically caused one. The described procedure was tested on the diametrically stressed glass disc.

The laser complex for the investigations of nonlinear properties of semiconductors has been designed. The results of the two-photon absorption coefficient of the chalcohenide glass As₂S₃ measurements are presented. The measurements accuracy and threshold sensitivity of the complex are estimated.

The schemes of monochromators based on photopolymer holographic transmission gratings are proposed. Two types of dispersion units with dispersion subtraction and addition are developed. Their resolving powers are correspondingly 1000 and 100,000. Temperature stability of parameters of gratings on photopolymers is investigated. It is determined the temperature range of diffraction efficiency conservation is 5 - 100 degrees Celsius.

In the paper we investigate the relationship of film composition prepared in conditions of joint oxidative hexacarbonyls thermodecomposition to the ratio of molybdenum and tungsten hexacarbonyls vapors pressure. The films are prepared in vacuum on the order of hundreds pascal in the flow reactor by controlling the deposition process. As an oxidizer we used air. The vapor pressure measured by means of thermoelectric converters using the technique to an accuracy of 5%. The film thickness was on the order of hundreds of nanometers. For substrate we used monocrystal silicon. The film composition was determined by layer-by-layer auger spectroscopy method. The investigations were pursued on the JSM-T-20 auger analyzer by internal standards method in conditions of continuous film surface etching in an argon ion beam.

The capabilities of the hybrid optical/digital system for nondestructive testing of high- temperature melts, liquid metals, and liquids by sessile drop method were studied. The spatial- temporal noises and spatial (geometric) noises of the system were analyzed and measured. The spatial-temporal noise caused by sessile drop's lateral oscillation were marked and measured. The experimental dependencies between noises variances and relative illumination of sessile drop images are obtained. The functional connection between the maximum variance of the sessile drop's random lateral oscillation noise and the surface tensions of studied substances was found.

Chalcogenide glasses possess comparatively large sensitivity on outer influence (light, heat) that determine their application in optical sensing devices and optical information processing systems based on light absorption or refraction. For this reason theoretical background of optical parameters prediction was considered and certain Ge-Sb-Se-type glass compositions were developed and investigated for fiber optic, sensing elements.

For measurements of reflection factor of recording cover, deposited on internal surface of glass cylindrical tube, we designed and manufactured a stand. It permits us to conduct the measurement of reflection factor of recording cover of optical information carrier within a time of not more than 25 s. The measurement of reflection factor is conducted on an 0.83 mkm wavelength of semi-conductor infrared laser. We admit the measurement of reflection factor for samples on flat substrates.

The problem of heating of semiconductor surface and its subsurface layers in the case of pulse laser irradiation is theoretically considered. It is supposed that heating is due to surface recombination of nonequilibrium carriers. The time dependencies of temperature for different values of a surface recombination are given. The obtained heating dependencies can be used for analysis of a surface quality.

The method and installation for defining the dynamic viscosity coefficient, electric resistance coefficient, in thin layers of dielectric and semiconductor materials in stringy state are represented.

The systematic errors that appear in the course of measurements by the methods of high- accuracy polarimetry are considered. The polarizing prisms are revealed to cause those errors. Because of parasitic ellipticity of the emergent light and inaccuracy in orientation of the corresponding ellipses for the two prisms (polarizer and analyzer), measurements in experiment values involve a considerable quantity of unknown parameters. For these reasons the determination of parameters of the investigated media (for example, the gyrotropy) are characterized by large experimental difficulties. One of the methods of high-accuracy polarimetry based on the use of the elliptical polarizer (polarizer and quarter wave plate) and measuring the emergent light azimuth is considered. An automatic polarimeter, in which the above-mentioned approach is realized, is built. The apparatus may be used both for measuring the main parameters of optical anisotropy of crystals (optical activity, linear birefringence, rotation of optical indicatrix, electro-optic and electrogyration effects) and testing of elements of polarization optics (polarizes, compensators, modulators, optical windows).

The structural peculiarities and the influence of electrolytic polishing, plastic deformation by rolling, and composition's modification on surface's atomic structure of amorphous ribbons have been studied. The experimental results obtained by means of spectroreflectopolarimetric and Fourier-spectroscopic techniques for some 3D-metal based disordered alloys are presented and discussed. The structural anisotropy of both sides of as-casted ribbons for amorphous alloys was found. The anisotropy was characterized by the difference of principal angles of incidence determined under two orthogonal orientations of ribbon: parallel and perpendicular to the p- direction respectively. It has been determined that electrolitical polishing of the ribbon's surface has not changed essentially the behavior of optical conductivity spectra. We determine that plastic deformation by rolling causes the increasing of intensity of free electrons scattering on structural defects due to the enhancement of their concentration.

According to studies carried out in this work the character of the narrow band filter (NBF) parameters of transmission band depend substantially on the irradiation method and on spectral composition of light. Both spectral and expositive dependencies of photoinduced changes of transmission band parameters of structures were evaluated at wavelength (lambda) equals 0.442 micrometer and 0.633 micrometer.

An interferometer based on multimode light-guide bundles is described in the report. The main characteristic feature of the proposed scheme is inclusion of a functionally important element - - corrector compensating for the interfering signals field distortions induced by a light-guide channel. The paper considers the proposed scheme and inclusion of a functionally important element -- a corrector compensating for the interfering signals field distortions induced by a light-guide channel. The paper considers the possibility of application of both regular and non- regular bundles equipped with corrective nozzles of various types. The possibility of exploiting the interferometer with its light-guide channels subjected to specific disturbances is examined. We have examined the feasibility of transferring both interferogram image and interfering fields apart through the bundle. Thus, it has been found out that interferometric information can be transferred easily enough with bundles 100 - 300 mm long for the specimens of cross-section 5 multiplied by 5 square mm - 10 multiplied by 10 square mm. Under the most favorable conditions of the experiment it is possible to reliably transfer the information about changes in specimens of 100 multiplied by 100 square mm through the bundles 1000 - 2000 mm long. For the hologram recording common photomaterials (photorefractive crystals and thermoplastic chamber) were used.

A null-polarimetric method for the orientation of single crystals is developed based on the use of a high-accuracy null-polarimeter. The principles of accurate polarimetric measurements are discussed. The origins of the systematic instrumental errors due to imperfection of polarizers are analyzed. Analytical relationships are derived for the characteristic azimuths of both the incident and the emergent from crystal lights. The fitting of those data allows us to orientate crystals with the accuracy of about 10^-5 rad. The working procedures of orientation and the relevant experimental set-up are described.

In this work we suggest procedure that permits us to define phenomenological relations of observable polarization characteristics and statistical parameters of scattered light for non- uniform spatially polarized speckle pattern. It is based on the multiparametric regression model, which is obtained by numerical simulation of light scattering. Regression models have been constructed and their parameters' identification has been done for two detector aperture configurations: circular and two-point. In the latter case the analytical expressions for polarization moments as the functions of initial characteristics of electromagnetic field have been received too. This enables us to receive the quantitative estimation of regression model validity and precision of computer simulation.

For technological optimization of CdHgTe crystals used widely in IR-photodetectors the mechanisms of principal (theoretical) limitation of carrier concentration, mobility, and lifetime were investigated in the result of thermo and ultrasonic treatments. Next new phenomena and peculiarities of non-equilibrium processes were determined. Experimentally and theoretically minimum of lifetime concentration dependence was obtained when equilibrium carrier concentration was variated due to modification of acceptor (mercury vacancies) concentration. For 'weak' p-type conductivity crystals in low for holes magnetic fields the simple analytical Hall coefficient magnetofield dependence was justified. That permitted us to control electron and hole concentrations and mobilities for practically intrinsic material. Recombination-sized effect dealt with dependence of characteristic diffusion length on macrodefect size and configuration was obtained. Thermoacoustic processes of mercury vacancy generation and 'cure' were investigated.

The temporary evolution of spontaneous gratings (SG), induced by a linearly polarized single laser beam ((lambda) _r equals 632.8 nm and 441.6 nm) in thin AgCl-Ag films, is studied. It is found that the period of the gratings increases (decreases) as the laser exposition at 632.8 nm (441.6 nm) increases. This effect was explained by a generation of SG on waveguide modes scattered in films and by an existence of a colloidal Ag absorption band at 500 nm in the initial AgCl-Ag films. Percolation effects were found in the dependence of the halfwidth of diffraction reflexes on the exposition.

Film deposition parameters affect on the photographic characteristics (sensitivity and image contrast) of As₂S₃ films used as recording media for the optical storage has been investigated.

Hereby theoretical peculiarities and experimental potentialities of optical waveguide diagnostics (measurement error of effective mode refractive index approximately 10^-4) are reviewed, as well as elements and devices of integrated optics based on them. The special set-up, providing automatic processing of measuring information due to universality and using program library, are shown.

Well-known methods of optical diagnostics, database for their storage, as well as expert system (ES) for their development are analyzed. A computer informational system is developed, which is based on a hybrid ES built on modern DBMS. As an example, the structural and constructive circuits of the hybrid integrated-optical devices based on laser diodes, diffusion waveguides, geodetic lenses, package-free linear photodiode arrays, etc. are presented. The features of methods and test results as well as the advanced directions of works related to the hybrid integrated-optical devices in the field of metrology are discussed.

Common principles of development and application of reverse electrographic and electrophotographic material with thermoplastic treatment are discussed. Possibilities of purposeful modification of these materials by intrachain doping on the stage of synthesis or by macromolecular design methods are shown.

Hg_1-xCd_xTe (x approximately equal to 0.205, 0.27) 64 photodiode hybrid linear arrays for spectral regions (lambda) approximately equal to 3 - 5 and 8 - 12 micrometer have been designed. The p⁺-n-diodes were As-diffused n-type indium doped single crystals (n approximately equal to (2 - 5) 10¹⁵ cm^-3) delineated with standard wet photolithography technique. Surface leakage current at T equals 80 K seems to be the dominant current mechanism for the diodes with no passivation coating. At higher temperatures the generation-recombination mechanism was found to be the principal one. Diodes had mean detectivity values D^* (10.5 micrometer, 500, 1) approximately equal to 2 10¹⁰ and D^* (6.0 micrometer, 500, 1) approximately equal to 6 10¹⁰ cm Hz^1/2W^-1 at 80 K. The arrays were interconnected to silicon direct injection readout devices with CCD multiplexers which consist of input circuits, shift register and output circuits. The dynamical range was estimated to be of the order of 60 dB at T equals 80 K. The two-phase p-channel CCD shift register was designed with clock frequency operation $less than or equal to 5 MHz. Transfer efficiency without fat zero was 0.99985 at 1.0 MHz frequency. The control interface based on 16-channel, 10-bit A/D converter was developed for computer data recording and signal processing.

A rapid multichannel system is developed for infrared (IR) and mm wave investigations. This system is designed for observation of solar like objects and investigations of solar atmosphere correlations. It consists of two optical channels, separated by the dichroic element on the IR/visible and mm wave bands.