Transverse pattern formation and spectral characteristics of cw light beams in resonant media: an improved numerical simulation technique and mode analysis

Derbov, Vladimir L.; Melnikov, Leonid A.; Novikov, A. D.; Potapov, S. K.

doi:10.1364/josab.7.001079

Cited by 28 publications

(4 citation statements)

References 17 publications

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“…For example, self-focusing increases the concentration of energy in the axial region for a Gaussian peak. This enhances saturation of the resonance transition and decreases the local absorption coefficient [20]. On the other hand, defocusing of the beam leads to its transverse spreading and an increased fraction of absorbed energy per unit area of beam.…”

Section: Discussion Nonlinear Absorption Of Singular Light Beamsmentioning

confidence: 99%

Transformation of singular light beam transverse structure in resonant media

Romanov

Толстик

2008

J Appl Spectrosc

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535.34The peculiarities of transformation of transverse structure for singular light beams propagating in a resonant medium have been analyzed theoretically. The influence of nonlinear absorption, self-focusing, and defocusing on the characteristics of optical vortices with different topological structure has been studied. The formation conditions and parameters for singular spatially localized structures have been characterized. Introduction.A screw dislocation of a light-beam wave front appears as a screw surface with a special point at which the field amplitude is equal to zero and the phase is undefined [1]. A phase shift in multiples of 2π occurs if this singularity is avoided. Light beams with wave-front dislocations (optical vortices) that are observed in optical fields with a complex transverse structure [2] and in laser cavities [3] or are produced as a result of light diffraction on computer synthesized holograms [4] are constantly of interest to researchers because of numerous potential applications.The propagation of singular light beams in nonlinear media is investigated in order to find the stability conditions of their transverse and topological structure [5,6], to study the waveguide properties of transverse localized optical vortices in media with different types of nonlinearity [7-9], to analyze their polarization structure [10], and to develop methods for transforming the topological structure through nonlinear interactions [11,12]. Transformation of the transverse structure of Bessel light beams in various nonlinear materials is widely investigated together with singular beams [13][14][15].Herein features of the transformation of the transverse structure of singular light beams with the combined influence of nonlinear absorption and self-focusing (defocusing) of the radiation in resonant media are analyzed and the conditions for forming localized transverse structures as dark soliton vortices are determined. The model of resonant media that is used is suitable for describing the interaction of radiation with dye solutions and with activated crystals, crystals with color centers, and vapors of complex organic compounds.Theoretical Model of the Propagation of Singular Light Beams in Resonant Media. The propagation of singular light beams in resonant media will be investigated using a truncated wave equation for the complex amplitude of field E of the form [16]:

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Section: Discussion Nonlinear Absorption Of Singular Light Beamsmentioning

confidence: 99%

Transformation of singular light beam transverse structure in resonant media

Romanov

Толстик

2008

J Appl Spectrosc

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“…Within the framework of the scalar paraxial approximation an algorithm for direct numerical solution of relevant Maxwell-Bloch equations was developed using the decomposition in terms of Gauss-Laguerre modes for the transverse field pattern and the second-order implicit scheme for propagation. We revealed the appearance of transient features in the well-known self-induced lens and aperture effects, thoroughly studied in CW beams (see, e.g., [2][3][4][5][6]). Some features attributed to transient near-resonance selffocusing of a frequency-modulated beam have been earlier observed experimentally in the formation of sub-Doppler saturated absorption dips [7].…”

Section: Introductionmentioning

confidence: 90%

Transient Phenomena and Time-Dependent Resonance Self-Action in Phase-Modulated Laser Beams

Derbov

Serov

Пластун

et al. 2007

2007 9th International Conference on Transparent Optical Networks

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Transient behaviour of a phase-modulated laser beam in a two-level saturable absorber is studied basing of full spatio-temporal scalar numerical model. Joint effect of delayed self-focusing and transient response of the medium are shown to manifest themselves most clearly in the dependence of the output intensity of the beam upon its input instantaneous frequency, which is most relevant in spectroscopic measurements.

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“…The method is based on the use of the Galerkin criterion on the basis of a small number of flexible Gaussian modes. The system of ordinary differential equations, with the beam parameters obeying this equation, is easily solved numerically and can be qualitatively analysed [59,60]. Quasi-analytical method for the analysis of rectangular waveguide structures with step discontinuities is proposed in [61].…”

Section: Semi-analytical Methodsmentioning

confidence: 99%

Methods for description of the total field propagation in the irregular dielectric waveguides

Bekker,

Romanova

2001

JTIT

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Numerical and semi-analytical methods useful for analysis of the total field propagation in dielectric waveguides with sharp and smooth discontinuities are reviewed. The efficiency of these methods to model the field propagation in such structures is discussed comparatively. As an example, spatial transient regime of the radiation field propagation in planar step-index waveguide excited by a Gaussian beam is simulated numerically by two different beam propagation methods.

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Transverse pattern formation and spectral characteristics of cw light beams in resonant media: an improved numerical simulation technique and mode analysis

Cited by 28 publications

References 17 publications

Transformation of singular light beam transverse structure in resonant media

Transformation of singular light beam transverse structure in resonant media

Transient Phenomena and Time-Dependent Resonance Self-Action in Phase-Modulated Laser Beams

Methods for description of the total field propagation in the irregular dielectric waveguides

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