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| Current Research: Optical Solitons |
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Optical Solitons and
Vortices
Solitary waves, commonly referred to as solitons, have been
the subject of intense theoretical and experimental studies in many
different fields, including hydrodynamics, nonlinear optics, plasma
physics, and biology. In the context of nonlinear optics, solitons are
classified as being either temporal or spatial, depending on
whether the confinement of light occurs in time or space.
Temporal solitons represent optical pulses that maintain their shape,
whereas spatial solitons represent self-guided beams that remain confined
in the transverse directions orthogonal to the direction of propagation.
Both types of solitons evolve from a nonlinear change in the refractive
index of an optical material induced by the light intensity, a phenomenon
known as the optical Kerr effect. A spatial soliton is formed when
self-focusing of an optical beam balances its natural diffraction-induced
spreading. In contrast, it is the self-phase modulation that counteracts
the natural dispersion-induced broadening of an optical pulse and leads to
formation of a temporal solitons.
We are also ineterested in the self-similar behavior of nonlinear waves.
In this case, the beam profile (or pulse shape) evolves in a fashion such
that its width and phase change but the shape remains the same. In a recent
PRL, we presented exact analytical solutions describing
spatial bright and dark self-similar solitons inside graded-index waveguide
amplifiers. We are now investigating the possibility of nonlinear imaging of
optical and matter-wave vortices in nonlinear media. Figure above shows how
such a vortex fiorst contacts in size, becomes self-imaged at a certain
distance before expanding rapidly.
Recent Publications
- S. A. Ponomarenko and G. P. Agrawal, "Asymmetric incoherent vector
solitons," Phys. Rev. E 69, 036604 (2004).
- S. A. Ponomarenko, N. M. Litchinitser and G. P. Agrawal, "Theory of
incoherent optical solitons: Beyond the mean-field approximation"
Phys. Rev. E 70, 015603 (2004).
- S. A. Ponomarenko and G. P. Agrawal, "Linear optical bullets"
Opt. Commun. 261, 1-4 (2006).
- S. A. Ponomarenko and G. P. Agrawal, "Do spatial soliton-like
self-similar waves exist in nonlinear optical media?"
Phys. Rev. Letts. 97, 013901 (2006).
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