Biomedical subjects

Milutin Stepić

Publications and source records attributed to Milutin Stepić.

6 recordsLinked to original sources

PubMed2006

Beam interactions in one-dimensional saturable waveguide arrays.

The interaction between two parallel beams in one-dimensional discrete saturable systems has been investigated using lithium niobate nonlinear waveguide arrays. When the beams are separated by one channel and in phase it is possible to observe soliton fusion at low power levels. This result is confirmed numerically. By increasing the power, solitonlike propagation of weakly coupled beams occurs. When the beams are out-of-phase the most interesting numerically obtained result is the existence of oscillations which resemble the recently discovered Tamm oscillations.

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PubMed2006

Observation of staggered surface solitary waves in one-dimensional waveguide arrays.

The observation of nonlinear staggered surface states at the interface between a substrate and a one-dimensional self-defocusing nonlinear waveguide array is reported. Launching of staggered input beams of different power in the first channel of the array results in formation of localized structures in different channels. Our experimental results are confirmed numerically.

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PubMed2006

Observation of modulational instability in discrete media with self-defocusing nonlinearity.

We report what we believe is the first observation of modulation instability in the anomalous-diffraction regions of a photonic lattice. The experiments were carried out in a 1D waveguide array fabricated in a lithium niobate crystal displaying the photovoltaic self-defocusing nonlinearity, and our results are confirmed numerically by simulating the nonlinear beam propagation.

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PubMed2004

Power controlled soliton stability and steering in lattices with saturable nonlinearity.

Dynamical properties of discrete solitons in nonlinear Schrödinger lattices with saturable nonlinearity are studied in the framework of the one-dimensional discrete Vinetskii-Kukhtarev model. Two stationary strongly localized modes, centered on site (A) and between two neighboring sites (B), are obtained. The associated Peierls-Nabarro potential is bounded and has multiple zeros indicating strong implications on the stability and dynamics of the localized modes. Besides a stable propagation of mode A, a stable propagation of mode B is also possible. The enhanced ability of the large power solitons to move across the lattice is pointed out and numerically verified.

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PubMed2004

One-dimensional bright discrete solitons in media with saturable nonlinearity.

A problem of pulse propagation in a homogeneous nonlinear waveguide array with saturable nonlinearity is studied. The corresponding model equation is the discretized Vinetskii-Kukhtarev equation with neglected influence of diffusion of charge carriers. For periodic boundary conditions, exact homogeneous and oscillating stationary solutions are found. A wide instability region of the homogeneous, array-independent solution is identified. An approximate analytical solution for the bright one-dimensional discrete soliton where the energy is concentrated mainly in a few waveguides is obtained. The soliton stability is investigated both analytically and numerically and a cascade nature of the saturation mechanism is revealed.

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PubMed2002

Stability of one-dimensional array solitons.

The array soliton stability in the discrete nonlinear Schrödinger equation with dispersion for periodic boundary conditions is studied. The linear growth rate dependence on the discrete wave number and soliton amplitude is calculated from the linearized eigenvalue problem using the variational method. In addition, the eigenvalue problem is solved numerically by shooting method and a good agreement with the analytical results is found. It is proved numerically that the results for the instability threshold for the circular array coincides with the quasicollapse threshold for the case of open arrays with initial pulses in a form of array solitons.

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