Purely organic materials with negative and near-zero dielectric permittivity can be easily fabricated, and propa- gation of surface polaritons at the material/air interface was demonstrated. Here we develop a mean- eld theory of nonlinear light-induced "plasmonic" properties of organic materials. The theory describes both a red shift of the resonance frequency of isolated molecules, according to the Clausius-Mossotti Lorentz-Lorentz mecha- nism, and the wide variations of their spectra related to the aggregation of molecules into J- or H-aggregates. The bistable response of organic materials in the condensed phase has been demonstrated using the electron- vibrational model. We predict the generation of the switching waves, or kinks in the bistable organic thin lms that enable us to observe a bistable behaviour of the surface polaritons at the organic thin lm/dielectric inter- face under the laser irradiation. We present the alternating-sign dependence of the switching wave velocity on pump intensity and discuss a possibility of controlling the polariton propagation by switching waves.
Radiation reaction radically influences the electron motion in an electromagnetic standing wave formed by two super-intense colliding laser pulses. Depending on the laser intensity and wavelength, the quantum corrections to the electron motion and the radiation reaction force can be independently small or large, thus dividing the parameter space into 4 regions. When radiation reaction dominates, the electron motion evolves to limit cycles and strange attractors. This creates a new framework for high energy physics experiments on the interaction of energetic charged particle beams and colliding super-intense laser pulses.
A new lasing mechanism for semiconductors like CuCl, CuBr is proposed based on the two-photon pumping of
biexcitons from the ground state of the crystal and generation or amplification of light in the region of M-band of
luminescence due to the optical exciton-biexciton conversion. It was shown that the net gain essentially depends on the
level of two-photon pumping and rapidly decreases deep into the crystal due to the spatial depletion of pump radiation.
Estimations for CuCl give the values of lasing photons with the energy about 3,2 eV and the maximum small signal gain
about the value of the exciton absorption coefficient.
A theoretical and numerical analysis of the transmission of phase modulated laser pulses through a thin film with
excitonic nonlinearity is performed. It is shown that, by choosing the modulation law, one can efficiently control the
optical nonlinearity of the film down to the inversion of the sign of nonlinearity.
The dynamics of free and optically induced decay of quasi-one-dimensional atomic Bose-Einstein condensates (BECs) is considered. The main characteristics of BEC modulation instability were found and compared for the cases of local and non-local interatomic interaction potential. The dynamics of BEC decay was studied numerically for the cases of positive and negative scattering length, absence or presence of optical standing wave, and for different shapes of initial BEC density distribution.
Paper present a review of theoretical study and numerical simulations of effects of nonparaxiality on spatial optical solitons in transparent media with various types of optical nonlinearity: Kerr-law and saturating self-focusing non linearities in isotropic media and second-order nonlinearity in anisotropic media. The main features of spatial solitons, including their stability, transient process, and polarization characteristics are found. Conjunctions for formation of 'optical needles' - spatial solitons with sub- wavelength width - are formulated.
We have performed a theoretical analysis of conditions of existence and stability of coupled dissipative solitons in an interferometer with a threshold-type of nonlinearity driven by external coherent radiation. For two-soliton structures we demonstrate splitting of spectrum of soliton width. For periodic structures of solitons we found zonal spectrum of characteristics. We studied analytically effect of small- and large-scale inhomogeneities of characteristics of the driven radiation and optical cavity on main features of dissipative optical solitons.
The scenario for stability loss of laser solitons is analyzed. The process of radial symmetry breaking and bistability between symmetrical and rotating solitons is demonstrated. New, rotating and oscillating soliton state is founded. The consequent period-doubling of symmetrical oscillations is found as a route to chaotic behavior.
In recent experiments of M. Gruneisen et al., the possibility was shown to record the so-called 'blazed' dynamic holograms in optically addressed liquid crystal spatial light modulator (OA LC SLMs). In such holograms the phase retardation distribution across the holographic fringe has a saw-like shape (asymmetrical triangle). Such holograms can provide a very high (in a limit - nearly 100%) diffraction efficiency. In previous experiments such 'blazed' holograms were recorded with the use of digital computer methods. We propose a novel, analogous an completely optical approach to the record of such holograms. One can record a saw-like profile of phase retardation in an OA SLM, placed into the nonlinear interferometer. In such interferometer the probe wave reads out the phase retardation in SLM, interferes with reference wave, and the phase retardation in the said SLM is controlled by their interference pattern. The results of the direct numerical simulation of the system show that by this method can be formed the saw-like grating, providing nearly 100% diffraction efficiency. Presented is the analysis of the system dynamics and stability.
Paper presents the results of semianalytical study of features and stability of weakly nonparaxial spatial (transversely two- dimensional) optical soliton in a transparent bulk medium with a cubic (Kerr-law) nonlinearity. We have developed a variant of perturbation theory for sufficiently wide solitons where a small parameter of nonparaxiality is the ratio of the light linear wavelength to the soliton width. By solution of approximate governing equation for electric field transverse components with the Townes mode with linear polarization as an initial iteration, we have found solitons with cylindrically asymmetric field distribution and elliptical polarization changing over the transverse section. The nonparaxial soliton stability was confirmed and weakly damping 'internal modes' of the soliton have been found.
Paper presents the results of theoretical study and numerical simulations of the laser bullets--3D dissipative optical solitons in continuous media with saturable resonance amplification and absorption, constant (non- resonant) absorption, and quadratic frequency dispersion. We have performed bifurcation analysis of stationary symmetric bullets, have determined conditions of their existence in dependence of frequency detunings, investigated possibility of existence of topological 3D dissipative solitons, and studied different regimes of interaction of two laser bullets.
We propose a method of numerical simulation of an image formation in vision systems looking through the waved water surface. The simulation of radiation propagation through the waved sea surface and sea depth is realized in ray approximation. Waviness is simulated as evolving in the time random surface with given spectrum of elevations and dispersion relation. New values of angular, energy, and polarization parameters of each ray in the beam after its refraction and reflection at a given surface point are calculated by means of Fresnel formulae. Seawater medium is split in the layers with thickness chosen from the condition that water characteristics can be considered as constant and that multiple scattering of a ray can be neglected within a layer. Attenuation of beam energy corresponds to the length of the beam path in the layer, and probability of beam scattering at a random angle within a layer is determined by phase scattering function. We have obtained numerically instantaneous and averaged over different exposition times images of 2D self-luminous and located mira made up from spokes and situated at various depths for various values of wind velocities and seawater scattering coefficients. Influence of water and waviness parameters on the image quality has been analyzed.
We present results of direct computer simulations of formation of laser bullets--3D localized (soliton-like) structures of coherent radiation in media with saturable optical absorption and amplification and frequency dispersion. Stable stationary symmetric and pulsing asymmetric laser bullets are demonstrated. Superstability of these dissipative solitons and absence of drift of their main parameters give good reason to believe that these structures are promising for applications in the field of optical information processing.
A review and comparison are given of localized (soliton-like) structures with nonzero topological index in the two types of nonlinear optical systems: (1) homogeneous medium with nonlinearity of refractive index (conservative system), and (2) wide-aperture laser with saturable absorption (dissipative system).
We present results of theoretical investigations of collisions of spatial solitons. For the case of large collision angles the analytic theory has been worked out. Numerical investigations of power exchange among the solitons with small collision angles were carried out. The possibility of new soliton creation after collision has been discovered.
Transversely 2D laser autosolitons--localized structures of light in wide-aperture lasers with saturable absorption--with different topological indices and rotating axially non-symmetrical intensity distribution are analyzed by means of computer simulations. Four different types of collisions of laser autosolitons are presented.
We demonstrate the principal possibility of regenerative amplification of laser-injector signal with given phase distribution by a ring reflective amplifier with self-conjugate resonator. Effects of amplifier optical deformation on formation of given wave front during amplification were studied. Frequency locking conditions of interjector-ring amplifier system have been considered.
Analysis of comparatively low-threshold interaction of laser radiation in vacuum is given. Efficiency of mixing of three waves with frequencies (omega) 1, (omega) 2, and (omega) 3 resulting in generation of combination mode with frequency (omega) 1 + (omega) 2 - (omega) 3 is studied. The possibility for demonstration of vacuum polarization phenomena in laser experiments is shown.
We present the results of computer simulations of laser diffractive autosolitons--particle-like field structures in the wide-aperture lasers with saturable absorber. Existence of transversely motionless and moving patterns in one- and two-dimensional laser schemes is demonstrated.
We describe basic properties of particle-like light structures (diffractive autosolitons) in wide- aperture nonlinear interferometers irradiated by external coherent radiation. Basic principles of the discrete-analogous method are presented. They are based on autosolitons' features promising for high-performance and accurate processing of large arrays of information. The method is illustrated by results of computer simulations for schemes of multidigit optical full adder.
We present the results of theoretical investigations and computer simulations of switching waves and diffractive autosolitons in wide-aperture lasers with additional nonlinear elements, nonlinear interferometers, and arrays of optically coupled passive nonlinear cavities excited by laser radiation.
Analysis of photonic noise in wide-aperture nonlinear interferometer excited by external radiation is presented. The possibility of spatio-temporal squeezed states generation and of effective noise suppression in a definite range of temporal and spatial frequencies is demonstrated.
Hard excitation of particle-like field structures in passive nonlinear interferometers (diffractive autosolitons) under conditions of transverse structure instability and in the case of unstable resonator are investigated. The existence of positive and negative diffractive autosolitons in a wide-aperture laser with saturable absorber is shown.
The main features of field structures with characteristics of excitation in wide-aperture nonlinear interferometers driven by coherent external radiation are reviewed. Single and interacting switching waves and diffractive autosolitons are considered, including autosoliton interaction with dislocation of holding radiation wave front. The possibility of realization of digital-analogous parallel optical computing using these structures, spatial hysteresis, and reconstruction of interferometer regime under effect of radiation are discussed.
Specific laser applications in information systems for two important cases-nonlinear digital computing optical systems and coherent information laser systems-are described. Some new results obtained at the S. I. Vavilov State Optical Institute are presented. The state-of-the-art and possible applications of feedback nonlinear optical systems for digital parallel data processing are discussed. New possibilities produced by employing high-quality laser radiation in transverse distributed wide-aperture bistable systems are presented, and the main properties of such systems (spatial hysteresis, diffraction autosolitons, and switching waves) are discussed. A discussion of coherent information laser systems is included. The results obtained with high-performance neodimium-doped lasers are reviewed. The amplification of single-frequency cw laser radiation in a pulsed solid state amplifier is discussed. Finally, some theoretical and experimental results concerning the frequency purity of amplified signals are presented.
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