141 research outputs found
Optical vortices in dispersive nonlinear Kerr type media
The applied method of slowly varying amplitudes of the electrical and magnet
vector fields give us the possibility to reduce the nonlinear vector
integro-differential wave equation to the amplitude vector nonlinear
differential equations. It can be estimated different orders of dispersion of
the linear and nonlinear susceptibility using this approximation. The critical
values of parameters to observe different linear and nonlinear effects are
determinate. The obtained amplitude equation is a vector version of 3D+1
Nonlinear Schredinger Equation (VNSE) describing the evolution of slowly
varying amplitudes of electrical and magnet fields in dispersive nonlinear Kerr
type media. We show that VNSE admit exact vortex solutions with classical
orbital momentum and finite energy. Dispersion region and medium
parameters necessary for experimental observation of these vortices, are
determinate.
PACS 42.81.Dp;05.45.Yv;42.65.TgComment: 24 page
The light filament as vector solitary wave
We present an analytical approach to the theory of nonlinear propagation of
femtosecond optical pulses with broad-band spectrum in gases. The vector
character of the nonlinear third-order polarization is investigated in details,
taking into account the carrier to envelope phase. The corresponding system of
vector amplitude equations is written by using left-hand and right-hand
circular components of the electrical field. We found that this system
nonlinear equations admits vector soliton solution with Lorentz shape.
The solution presents relatively stable propagation and rotation with GHz
frequency of the vector of the electrical field in plane, orthogonal to the
direction of propagation. The evolution of the intensity profile demonstrate
weak self-compression and week spherical wave in the first milliseconds of
propagation.Comment: 5 pages, 1 figur
Vortex solitons in dispersive nonlinear Kerr type media
We have investigated the nonlinear amplitude vector equation governing the
evolution of optical pulses in optical and UV region. We are normalizing this
equation for the cases of different and equal transverse and longitudinal size
of optical pulses, of week and strong dispersion. This gives us the possibility
to reduce the amplitude equation to different nonlinear evolution equations in
the partial cases. For some of these nonlinear equations exact vortex solutions
are found. Conditions for experimental observations of these vortices are
determined.Comment: 28 pages, 9 figures, Late
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