Laser micro-machining offers the ability to cut more complex patterns with less damage to delicate materials than competing approaches. Here we review recent progress in laser micromachining of piezoelectrically active PZTs, ferroelectric single crystal perovskites, and laser applications to high density electrical interconnect problems; the methods discussed here have broad application to the development of devices down to the MEMS scale.

Laser is a powerful tool for precise spectroscopy and has been used in many different fields of physics. In this paper we present interesting and important examples of laser spectroscopy applied in the field of atomic physics involving an exotic particle `antiproton'. We have performed laser spectroscopy of metastable antiprotonic helium atoms (or atom-molecules) (pHe+) and have observed a density dependence of the resonance vacuum wavelengths for the known transitions (n,1) equals *(39,35) yields (38,34) and (37,34) yields (36,33).

A method of transformation of so called generalized Schrodinger equation with temporal derivation from nonlinear response and some results obtained with the help of this transformation is discussed in this paper. Our approach allows reviewing of results referring to the problem of development of modulation instability of ultra-short laser pulse. This approach may easily be applied to the problem of an interaction of laser light with photonic crystal.

We consider an affection of femtosecond laser pulse on nonlinear medium in the framework of thin layer and thick layer of medium. Laser pulse propagation is described by 1D non-stationary Maxwell equations together with nonlinear polarization equation. We compare results of mathematical modeling based on two types of description of polarization. The first of them uses a Duffing's approach. The second is based on application of electron-nuclear interaction potential with saturation. We investigate also an influence of laser pulse duration on a shift of spectrum polarization frequency of maximum amplitude.

Spatio-temporal dynamics of two short laser pulses propagating in an absorbing medium, which consists of one- and two-photon resonant (Lambda) -atoms, is investigated in the adiabatic approximation. We give an analytical solution and compare it with numerical simulations. It is shown that pulses may propagate in a medium, whose thickness is considerably greater than the length of the linear absorption of a single weak probe wave. Finally, full transfer of the probe pulse energy into the coupling pulse takes place. A vector model of the adiabatic interaction of two pulses with three-level atom is proposed.

Pitchfork bifurcation of stationary and periodic solutions, reflecting the invariance properties of equations of motion with respect to transformations of variables and parameters and corresponding to polarization symmetry breaking and restoration phenomena have been considered in a single-mode standing-wave class-A gas laser with linear phase anisotropy of the cavity at j yields j + 1 transition between the working levels.

In this work the numerical investigations of a potential dynamics of a neural network as the non-linear system and dynamics of the visual nerve which connect the eye retina receptors with the striate cortex cerebrum as the answer to the through-skin excitement of the eye retina by the electrical signal were realized. The visual evoked potential is the answer and characterizes the human brain state over the structures retina state and the conduction of the visual nerve fibers. The results of these investigations were presented. Specific features of the neural network, such as the excitation and depression, we took into account too. The discussion about the model parameters, used at the time of the numerical investigation, was made. The comparative analysis of the retina potential data and the data of the external signal filing by the brain hemicerebrum visual centers was made too.

Some quantum optical models possessing a transition from regular to chaotic dynamics and influence of `quantum chaos' to squeezing are investigated. Particular cases of semiclassical dynamics of a single atom and cooperative system of these atoms with (2j + 1)--equidistant levels interacting with a quantized photon mode in an ideal cavity were considered. Corresponding equations of motion are received without the rotation-wave approximation. Chaotic behavior and squeezing degree time dependence were obtained in computer simulations for coupling constant values or order of the atomic frequency.

The data on change of phase synchronism conditions at the second harmonic generation in the KD*P crystals are presented for the first time. This changes are due to the influence of arising at additional irradiation of the sample photorefraction. The calculation on the basis of the phenomenological model was compared to the experimental data and has revealed their basic divergence. Direct measurements of the induced by the photorefraction internal field in the sample are made for the first time. The definite photorefractive efficiency (up to 0,5 kV/nm of the internal electrical field at the energy of pulse irradiation are 1 - 2 tens J/nm²) point to necessity of the account it in the majority of situations, when the nonlinear-optical effects are excited.

We propose a stable numerical scheme for solving Schrodinger equations that arise in the scalar paraxial theory of optical waveguides as well as in the quantum mechanics of a particle in a potential field. The scheme makes use of a multi-coordinate version of the split-step approach combined with the complex scaling that assures the implementation of boundary conditions. Beam propagation in a Gaussian waveguide is considered to illustrate the ability of the scheme to account for both waveguide and radiation modes.

We show that under the condition of local field limitation the total power transported through a waveguide can be substantially increased using twisted astigmatic generalized Gaussian beams. Numerical modeling of such beams in a parabolic waveguide with Kerr nonlinearity is carried out basing on the modified generalized moments method. The conditions are found that provide the optimal propagation regime in which the fixed-size beam spot rotates uniformly around the beam axis. It is shown that in this regime the peak intensity of the beam may be sufficiently lower than in stable axially-symmetric beams of the same total power.

Photovoltaic current in high-temperature photorefractive DKDP crystal is measured directly using the original technique based on the current-to-voltage converter operating in the pulse regime. Theoretical consideration of the mechanisms involved and estimates of the observed values are presented. On the basis of the dislocation model we succeeded to get quantitative agreement with the existing experimental data in the value of photoinduced electrical field as well as in the dynamics of both the PR response and the photovoltaic current.

Coherent population trapping effect is widely studied for simple three-level systems of different types ((Xi) , (Lambda) , V). For real atoms situation is more complicated. Atomic levels are degenerated one and in the presence of external fields coupling of magnetic sublevels appears due to as radiation, so magnetic fields, leading to the systems of levels of the higher order. Our theory and model of calculation for interaction of multilevel atom with intense radiation field at the presence of external magnetic field have been applied for considering coherent population trapping effect for such systems.

Propagation of a weak probe optical beam through a three- level medium pumped with a microwave strong beam is numerically studied. Three various schemes of transitions under the conditions providing the amplification of the probe field without inversion are taken to calculate the atomic polarization which enters the paraxial wave equations. Diffraction and self-action of beams due to nonlinear absorption and refraction are properly taken into account. These effects together with linear absorption and refraction form a complex distribution of gain across the beams. As a result the amplified beam acquires ring transverse patterns and slight asymmetry in the frequency characteristics.

We report the results concerning the regimes of transition to the temporal chaos in an optical system with the feedback based on the single-mode frequency-stabilized laser.

The superradiance (SR) of initially inverted two-level active medium in a cavity is considered. We discuss the results specific for the rigorous simulation of the SR pulse (obtained on the basis of 1D Maxwell-Bloch equations solution without slowly varying envelope approximation (SVEA) in the spatial variable): the strong dependencies of the counter-propagating waves correlation and pulse development acceleration not only on the module of the cavity mirrors reflection coefficient, but on the integer- factor of the ratio of the sample length and half of the resonant wavelength. The simple modification of the SVEA model approximately describing the above features is considered.

Speckle method of determination of relative displacement of two object areas as well as method of studying of micro relief dynamics has been applied for determination of non- reversible deformations of the cylindrical samples under tension. The technology allowing to register in real-time the picture of interference of two speckle non-homogeneous waves and the picture of speckle dynamics has been described. The 2D interference pictures and pictures of speckle dynamics have been presented. The results of studying of dynamics of transverse deformations and results of determination of localization area length of non- reversible deformations up to fracture of the samples have been reported.

Technological advances made possible microprocessing of optical and diffractive devices of subwavelength size. Such elements may find use in holography, spectroscopy, interferometry, and optical data processing. The rigorous modeling of these devices calls for solving the basic electromagnetic Maxwell's equations. If one needs to get a far-field solution, commonly used geometrical optics approximations become inadequate, which entails the necessity of developing numerical techniques for solving Maxwell's equations. For a subwavelength characteristic size of diffractive structures, one should use a vector model for analyzing diffraction processes [1]. The vector diffraction problem may be solved analytically for some periodic structures [2]. Hence, the vector diffraction by aperiodic DOEs should be simulated using numerical techniques. These numerical techniques may then be used in working out recommendations how to improve the parameters of fabricated devices or to optimize the process of developing new ones. The majority of numerical diffraction models aimed at analyzing conducting electromagnetic scatters may be divided into differential [3], integral, and variational. With integral methods, the electromagnetic field at a space point is found as a combination of contributions to this point from source fields, taken over space or surface. Popularity of the integral methods is due to their ability to deal with unlimited field problems since the Zommerfeld radiation condition holds unconditionally in the problem statement. Furthermore, the integral methods require that only the surface field of a diffraction element be known, and not the total spatial field, thus minimizing the number of unknowns. A disadvantage of the integral methods is that they lead to fully completed matrixes and, hence, require large bulk of computer memory and great computational efforts. Note that volume integral methods are also able to simulate diffraction by nonhomogeneous DOEs. Variational methods applied to solving limit-volume tasks find the solution to Helmholtz's equation by minimizing the functional relation, as opposed to directly solving differential equations. If the finite element method is stated using the Ritz method, it is represented by a variational approximation. Its statement is simple and apply to an arbitrary homogeneous medium. However, it involves no Zommerfeld radiation condition. It is common practice to use an absorbing boundary condition which is also not free from disadvantages. There is also a hybrid method [1] which implies the application of the finite element method (FEM) to the internal DOE region where nonhomogeneities may occur, and the application of the boundary element method to a DOE-external region, with the radiation conditions to be fulfilled. The methods meet on the interface, thus satisfying the field continuity condition. This approximation represents a faithful boundary condition since values of the normal derivative of reflected field are given exactly. A disadvantage of the method lies in the nondiagonal character of the matrix system, which leads to a completely filled submatrix resulting in a greater memory resources for data storage and great computational efforts

Advances in numerical methods and progress in the computer hardware made possible numerical solution of Maxwell's equations. Thus, imposing adequate boundary conditions and substituting into the equations medium parameters enables the simulation of light propagation in various media. We developed difference schemes making it possible to model optical processes that occur when various types of light waves travel through optical elements, such as diffractive lenses and antireflecting gratings.

The article proves the problem of determining the mechanical vibration amplitudes of complicated movements by optical homodyne interferometry to be incorrect. The possibility of its approximate solution by the least-squares method is presented. The above method usage for the restoration of mechanical system vibration spectrum has been verified.

Diffraction of radiation by the Cantor set based multifractals is studied. Connection between the dimension of an object's supporting fractal and its level is searched for as well as one between the multifractal's construction parameter, singularity spectra, and asymmetry parameters of its diffraction pattern. It has been shown that the singularity spectrum has a maximum whose position depends on the object's supporting fractal dimension. At the same time, a singularity spectrum half-width and near-field intensity's asymmetry coefficient occur to be acceptable for evaluation of the object construction ratio parameter, and magnitude of the asymmetry coefficient at saturation zone depends on the level of the object's supporting fractal.

The phenomenon of the light diffraction by the elastic waves in crystals has been considered on the basis of the coupled waves method in somewhat different form than it was earlier considered by other researchers. The difference is determined by the address to two pairs of the orthogonal coordinate systems whose main axes are oriented in the directions of the phase and the energy movements of two optic waves interacting via the `sound'. As a result the coupled mode equations are obtained in most compact, not complete previously known form for the crystals. They admit the traditional solutions in the form of the quasiplanar waves and assume more wide class of solutions for the restricted interaction regions. The comparative analyze of two different diffraction regimes--on transmission and on reflection--is made. The represented consideration allows to formulate in correct form the parameters, determining the light diffraction efficiency by elastic waves in crystals.

The effect of autodyne detection in semiconductor lasers generated relaxation oscillations has been investigated. The computer simulation of the experimentally observed blurring of phase trajectories on its certain parts has been made with the help of numerical calculation of the system of differential equations for semiconductor laser with vibrating external reflector. The relation of the blurring of trajectories with generation of relaxation oscillations on these parts has been found. It has been shown that semiconductor laser in the generation regime of relaxation oscillations has the high sensitivity to the fluctuations of parameters of external optical feedback and to the non- stability of power supply.

Details of the dislocation interaction with exitons in deformated crystals are considered. This phenomenon is studied by calculating method of energy dissipation caused by the quantum transitions of the excitons induced by external disturbance. The dependence of deceleration force via dislocation velocity in some ranges was obtained.

The experimental fact of an essential increase in optical, radiation and degradation firmness of heterogeneous optoelectronic material CdS-PbS is explained in terms of a difference in defect diffusion intensification under irradiation in the wide- and the narrow-band-gap components of the material. A quantity model of the firmness is proposed, and results of computer simulations performed in accordance with it are included which show that under exposure to optic and other kinds of radiation the mentioned difference in defect diffusion intensification makes the defects accumulate in the narrow-band-gap inclusions of CdS- PbS, which in turn leads to the increase in the firmness of the material.

The theoretical analyze of coherent acousto-optical interaction in the turbid medium resulting in the appearance of ultrasound modulation of the photo-detector current has been fulfilled. Analysis of the influence of tissue scattering properties and geometry of experiment on spatial resolution of technique of acousto-optical imaging by using of considered model is made. The relations between amplitude and phase of the ac current and the receiver system parameters are derived. The optimal conditions for measurements of the ac current on ultrasound frequency are determined. The experimental testing of these conditions have been accomplished with focused ultrasound wave at 3 MHz. The noise characteristics of detection system were studied as well.

Studies of primary mechanism of ozone formation in oxygen- containing mixtures and nonlinear refraction of gaseous xenon under the action of excimer laser radiation are reported. The dependence of ozone formation rate in compressed oxygen and in xenon-oxygen mixture on gas pressure and temperature was measured simultaneously with absorption measurements in the Herzberg band at two wavelengths of exciting radiation (248 and 224 nm). Analysis of experimental data shows that the primary mechanism of ozone formation under the action of KrF laser radiation is conditioned by the absorption of an oxygen molecule from the ground vibrational state in the Herzberg band with subsequent collisional dissociation of the excited molecule. The nonlinear contribution to the refractive index of high- pressure xenon at room temperature at the wavelength of XeCl laser radiation was measured with the help of the Twyman interferometer. Using the dependence of the shift of an interference pattern on the light intensity, the sign and the magnitude of the nonlinear contribution are obtained, which gave (Delta) n/<F₀²> equals -6(DOT)10^-12 electrostatic CGS unit. This value is shown to be determined by the balance of electrostrictional and electrocaloric mechanisms; it exceeds the electronic contribution to nonlinear refraction by two orders of magnitude.

To describe experiments on fluorescence excitation of single N-V defect centers in diamond we have used the double well potential (DWP) model which incorporates the possibility of tunneling the nitrogen atom into the vacancy both in ground and excited electronic states of the center. Fluorescence and linear absorption spectra are calculated, DWP's parameter values for N-V centers are determined and manifestations of their variations due to local diamond lattice distortions in fluorescence spectra of various single N-V centers are studied.

The present work is aimed at investigating the triplet- triplet excitation energy transfer process between dyes and polycyclic aromatic hydrocarbons in microheterogeneous micellar solutions of sodium dodecylsulphate. The result of the transfer is the sensitized room-temperature phosphorescence of polycyclic aromatic hydrocarbons observed for the first time. Spectral and photophysical properties of donor and acceptor solubilized in the micelles were studied, constants characterizing the `heavy atom' effect on the singlet and triplet states of the lumiphor were determined. The constant of the triplet energy transfer between triphaflavine (donor) and pyrene (acceptor) was obtained.

The opportunity of investigation of impurity defect properties in alkali halide crystals by study of the spectral characteristics of the strongly deformed crystals is shown. The spectral characteristics of KCl-In and NaCl-Ni crystals before and after deformation, and also after X- irradiation, are given. The effect of methods of impurity doping of a host crystal on spectral properties of powdered specimens under study was examined.

New formula for the matrix of finite rotation of normal coordinates during electronic transition is found. It has the property of orthogonality and is expressed via the eigenvectors of the matrix of kinematic coefficients and the matrix whose eigenvalues are the squares of molecular vibration frequencies. The formula was used for the calculation of the Duschinsky's matrix for the electronic transition A_1g - B_2u in the benzene molecule.

Methods of the calculation of the electronic wave functions of the ground and excited states, based on the MO LCAO approximation, do not limit the dimension of the basis of AO, although really all calculations of molecular electronic structure are limited by the valent AO. This limitation influences the properties of molecules in the ground state less than those of the excited states. The energies of the excited states and the transition dipole moments can depend on the dimension of the basis significantly. In this paper we modify the semi-empirical CNDO/S CI method of the calculation of energies and wave functions of molecules by completing the AO basis with non-valent 3p, 3d AO for the atoms of the second period of Mendeleev's table, which can participate in (pi) -type MO's. This modified method was used for the theoretical analysis of absorption spectra of benzene, naphthalene and diaminophtalimide molecules.

The research of temperature effect on optical spectra of benzophenone was carried out and the new interpretation of shuttle nature of temperature displacement of phosphorescence spectrum of benzophenone is given.

Studies of the dipole polarizabilities in a broad frequency range were recently reported for rare-gas atoms, in which the polarizabilities have been calculated on the basis of the modern experimental data on the differential dipole oscillator strength distributions in the resonance absorption spectra of He, Ne, Ar, Kr and Xe atoms. The calculated dynamic polarizabilities (alpha) ((omega) ) are found to be in a good agreement with the available and most reliable experimental data, the deviations being within the stated error bounds of the latter (0.1 - 0.2%). Calculations have been performed in the spectral range from the static limit up to the frequencies of the second atomic resonance transitions. Convenient analytic approximations for the (alpha) ((omega) ) functions are proposed, that are of superior accuracy compared to the commonly used three-term formulas for the polarizability dispersion.

The influence of H-bonds on formation of polymorphous modifications and mesomorphic states in the homologous series of alkylbenzoic, alkoxybenzoic, alkylcyclohexanecarboxylic acids, some of their fluorinated derivatives and in formyl-, hydroxy- derivatives of biphenyl in the five component LC mixture of 4-4'-alkyl-, 4-4-'alkoxy- derivatives of cyanobiphenyls has been discussed.

Depolarization of fluorescence of labeled macromolecules is determined by the second rank time orientational correlation functions (OCFs) of the absorption and emission dipole moments. To calculate the OCFs, macromolecules are conventionally modeled by the set of spherical particles (beads). To investigate the influence of the inertial and memory effects on the orientational relaxation, the diffusion equation with memory is used to perform illustrative calculations of the OCFs for a 2D system consisting of three beads joined by two rigid rods. These calculations reveal that under certain conditions the OCFs exhibit an oscillatory behavior, which is irreproducible within the standard diffusion equation.

Collisional depolarization of fluorescence is experimentally studied for 1,4-bis[2-(5-tolyloxazolyl)benzene] in He, Ar, and Xe solvents under the pressures ranging from zero to atmospheric. The results are interpreted within the Keilson- Storer model of the orientational relaxation and rigid body collision dynamics. The rate of the fluorescence depolarization vs. the buffer gas concentration is demonstrated to be very collision specific, thereby allowing one to extract information about the strength of the angular momentum scrambling in a binary collision.

Polarization response of photoisomerizing molecules under collisionless conditions is studied. General expressions are obtained for the fluorescence anisotropy in case of asymmetric top initial and isomer molecules, and for an arbitrary time between absorption of light and transition to an isomer state. The explicit calculations are performed for the steady-state anisotropy in several extreme cases. We show that detection of the polarized fluorescence offers one to estimate characteristic times of the reaction and to determine molecular orientation of absorption and emission dipole moments.

We report the results of numerical modeling of the coherent laser multi-pulse technique, proposed in our earlier papers to measure the population of the metastable states of antiprotonic helium and to control the decay kinetics in the adjacent transition chains. It is demonstrated that a sequence of properly chosen (pi) -pulses may result in a sequence of annihilation spikes whose amplitudes are nearly proportional to the populations of individual metastable states. The limitations related to the pulse duration and delay are studied as well as the role of the lifetime of the short-lived final state.