Defect modes in one-dimensional photonic lattices

Linear defect modes in one-dimensional photonic lattices are studied theoretically. For negative (repulsive) defects, various localized defect modes are found. The strongest confinement of the defect modes appear when the lattice intensity at the defect site is {\em non-zero} rather than zero. When launched at small angles into such a defect site of the lattice, a Gaussian beam can be trapped and undergo snake oscillations under appropriate conditions.Comment: 4 pages, 4 figure

Constitucionalidad de la ley de impuesto a las ganancias

En el presente trabajo se indaga acerca de la evolución histórica del Impuesto a las Ganancias en Argentina; abordar el tema señalado desde la perspectiva del derecho comparado a fin de darle una noción más global al lector sobre las diferencias y similitudes que hay con otros regímenes impositivos, en particular en los impuestos sobre la renta; siendo el objetivo principal y la problemática de nuestra investigación analizar la Ley de Impuesto a las Ganancias Nº 20.628 a efectos de establecer las posibles inconsistencias con respecto a la Constitución de la República Argentina.Fil: Esteban, Andrés Ezequiel. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas. Delegación San Rafael.Fil: Iwanow, Raisa. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas. Delegación San Rafael

Mobility of Discrete Solitons in Quadratically Nonlinear Media

We study the mobility of solitons in second-harmonic-generating lattices. Contrary to what is known for their cubic counterparts, discrete quadratic solitons are mobile not only in the one-dimensional (1D) setting, but also in two dimensions (2D). We identify parametric regions where an initial kick applied to a soliton leads to three possible outcomes, namely, staying put, persistent motion, or destruction. For the 2D lattice, it is found that, for the solitary waves, the direction along which they can sustain the largest kick and can attain the largest speed is the diagonal. Basic dynamical properties of the discrete solitons are also discussed in the context of an analytical approximation, in terms of an effective Peierls-Nabarro potential in the lattice setting.Comment: 4 page

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 new result is confirmed numerically. By increasing the power, soliton-like propagation of weakly-coupled beams occurs. When the beams are out-of-phase the most interesting result is the existence of oscillations which resemble the recently discovered Tamm oscillations.Comment: 5 pages, 6 figures, submitted to Phys. Rev.

Tamm oscillations in semi-infinite nonlinear waveguide arrays

We demonstrate numerically the existence of nonlinear Tamm oscillations at the interface between a substrate and one-dimensional waveguide array with both cubic and saturable, self-focusing and self-defocusing nonlinearity. Light is trapped in the vicinity of the boundary of the array due to the interplay between the repulsive edge potential and Bragg reflection inside the array. In the special case when this potential is linear these oscillations reduce themselves to surface Bloch oscillations.Comment: e.g.: 4 pages, 4 figures, submitted to Phys. Rev. Let