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Concepción, Chile

Bennet F.H.,Australian National University | Molina M.I.,University of Chile | Molina M.I.,Center for Optics and Photonics
Journal of the Optical Society of America B: Optical Physics | Year: 2012

We examine localized surface modes in the core of a photonic crystal fiber composed of a finite nonlinear (Kerr) hexagonal waveguide array containing a topological defect in the form of a central void. Using the coupled-modes approach, we find the fundamental surface mode and the staggered and unstaggered ring-shaped modes, and their linear stability windows, for two void diameters. We find that, for a small void diameter, the unstable unstaggered ring mode of the system always requires less power and its instability gain at low powers is smaller than in the case without the void. Also, for the small void case, the unstaggered ring mode does not require a minimum power threshold, in sharp contrast with the case without the void. For a larger void, most of these observations hold, as well. We follow numerically the dynamical evolution of these ring modes to reveal their decay channels at long propagation distances. © 2012 Optical Society of America. Source


Naether U.,University of Chile | Naether U.,Center for Optics and Photonics | Naether U.,Friedrich - Schiller University of Jena | Kartashov Y.V.,Polytechnic University of Catalonia | And 6 more authors.
Optics Letters | Year: 2012

We study the gradual transition from one-dimensional (1D) to two-dimensional (2D) Anderson localization upon transformation of the dimensionality of disordered waveguide arrays. An effective transition from a 1D to a 2D system is achieved by increasing the number of rows forming the arrays. We observe that, for a given disorder level, Anderson localization becomes weaker with increasing numbers of rows-hence the effective dimension. © 2012 Optical Society of America. Source


Martinez A.J.,University of Chile | Molina M.I.,Center for Optics and Photonics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We study discrete surface solitons in semi-infinite, one-dimensional, nonlinear (Kerr), quasiperiodic waveguide arrays of the Fibonacci and Aubry-André types, and explore different families of localized surface modes, as a function of optical power content ("nonlinearity") and quasiperiodic strength ("disorder"). We find a strong asymmetry in the power content of the mode as a function of the propagation constant, between the cases of focusing and defocusing nonlinearity, in both models. We also examine the dynamical evolution of a completely localized initial excitation at the array surface. We find that, in general, for a given optical power, a smaller quasiperiodic strength is required to effect localization at the surface than in the bulk. Also, for fixed quasiperiodic strength, a smaller optical power is needed to localize the excitation at the edge than inside the bulk. © 2012 American Physical Society. Source


Mejia-Cortes C.,University of Chile | Mejia-Cortes C.,University of the Atlantic | Mejia-Cortes C.,Center for Optics and Photonics | Molina M.I.,University of Chile
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We study a one-dimensional binary optical lattice in the presence of diagonal disorder and alternating gain and loss, and examine the light transport phenomena for localized and extended input beams. In the pure PT-symmetric case, we derive an exact expression for the behavior of light localization in terms of typical parameters of the system. Within the PT-symmetric region light localization becomes constant as a function of the strength of the gain and loss parameter, but outside the PT-symmetric window, light localization increases as the gain and loss parameter increases. When disorder is added, we observe that the presence of gain and loss inhibits (favors) the transport for localized (extended) excitations. © 2015 American Physical Society. Source


Molina M.I.,University of Chile | Miroshnichenko A.E.,Center for Optics and Photonics | Miroshnichenko A.E.,Australian National University | Kivshar Y.S.,Center for Optics and Photonics
Physical Review Letters | Year: 2012

We introduce a novel concept of surface bound states in the continuum, i.e., surface modes embedded into the linear spectral band of a discrete lattice. We suggest an efficient method for creating such surface modes and the local bounded potential necessary to support the embedded modes. We demonstrate that the surface embedded modes are structurally stable, and the position of their eigenvalues inside the spectral band can be tuned continuously by adding weak nonlinearity. © 2012 American Physical Society. Source

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