Formation of the Nonlinear Dynamic Hologram in Clear Organic Fluids

The recording of dynamic holograms during multiwave interactions in clear organic fluids (ethanol, acetone, dioxan, etc.) is investigated. It is shown that the fifth-order nonlinearities and higher become activated along with the cubical nonlinearity under the intense laser excitation (~100 MW cm –2 ) in the near-IR spectral range, which allows visualization of the IR images using different orders of diffraction

Providence Independent, V. 8, Thursday, December 14, 1882, [Whole Number: 392]

[4] p. “Persistent in the Right – Fearless in Opposing Wrong.” Newspaper published in Trappe, Pa. Weekly. Contains local, national and international news, fiction and advertisements.https://digitalcommons.ursinus.edu/providence/1172/thumbnail.jp

Wave front transformation of optical vortices with multiwave interactions in resonant media

The transformation of singular light beams is analyzed theoretically for multiwave interactions on amplitude and phase dynamic holograms in media with a resonant nonlinearity. The possibility of multiplying topological charge using different diffraction orders is demonstrated and optimal conditions for parametric energy exchange are determined which ensure retention of the structure of the wave front of optical vortices

Transverse Effects under Four-Wave Coupling in the Nonlinear Fabry–Perot Interferometer

Specific features of the light-beam transverse structure transformation in the process of four-wave coupling in the Fabry–Perot interferometer with a resonant nonlinearity under conditions of bifurcation of the symmetry breaking and optical bistability are analyzed. The asymmetric regimes of the interaction, characterized by a difference both in the integrated transmission functions of the nonlinear interferometer for two light beams with equal intensities and in the spatial intensity distribution at the exit of the interferometer, are considered

Multiwave Mixing of Singular Light Beams in Resonant Media

A method for transforming the topological structure of a singular light beam under multiwave mixing in the media with resonant nonlinearity is justified theoretically. The effect of self- and cross-modulation of the light waves under condition of nonlinear variation of the refractive index on stability of the optical vortices appearing in the multiwave mixing is studied

Spin-orbital Conversion of Bessel Light Beams By Liquid Crystal Elements

For the first time, the spin-orbital conversion of the linearly polarized Bessel beams in the process of their propagation in the electrically-controlled liquid crystal cell has been realized experimentally. Variations in the polarization, phase, and spatial structure of the beam have been analyzed. It has been shown that, when a Bessel beam is propagating along the liquid crystal director, the generated beam is orthogonally polarized, whereas the topological charge is varied by two unities. Keywords: Bessel light beams, spin-orbital conversion; liquid crystal

Photoinduced Absorption in Bismuth Titanate Crystals on Nano- and Picosecond Excitation

The peculiarities in the induced absorption of bismuth titanate (Bi12TiO20) crystals upon their irradiation by high intensity nano and picosecond pulses with a wave length of 532 nm have been studied. The relationship between the photochromic effect and radiation intensity at the fixed radiation dose in con ditions of pulsed laser excitation has been established. A threshold character of the relationship between the photochromic effect and intensity has been found for the first time. A phenomenological model making it possible to explain qualitatively the dynamics of the trapping level population process has been proposed

Control of optical bistability and complex dynamics of a nonlinear interferometer

Transfer functions and dynamic characteristics of a Fabry-Perot interferometer with a multilevel resonant medium have been studied theoretically under conditions of two-frequency excitation when one of the light beams had no resonator feedback. An incoherent control method, using absorption of an independent light beam by molecules in excited energy states, has been proposed for the bistable and dynamic characteristics of a nonlinear Fabry-Perot interferometer

Multiwave Mixing in Complex Molecular Media and Dynamic Modes of Light-Wave Transformation

The mechanism of multiwave mixing realized in solutions of complex organic compounds (dyes), in conditions when higher-order nonlinearities are exhibited along with the cubic one, has been analyzed theoretically and tested experimentally. Nonlinear recording of dynamic holograms enables signifcant improvement of the potentialities of holographic methods used for image conversion due to switching from phase conjugation to smoothing and amplification of the wavefront spatial structure. It has been demonstrated that a nonstationary energy exchange between the interacting waves is the cause for transition from the optical bistability mode to the mode of intensity self-oscillations