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ABSTRACT: We report dynamic regimes supported by a sharp quasi-one-dimensional (1D) ("razor"), pyramid-shaped ("dagger"), and conical ("needle") potentials in the 2D complex Ginzburg-Landau (CGL) equation with cubic-quintic nonlinearity. This is a model of an active optical medium with respective expanding antiwaveguiding structures. If the potentials are strong enough, they give rise to continuous generation of expanding soliton patterns by a 2D soliton initially placed at the center. In the case of the pyramidal potential with M edges, the generated patterns are sets of M jets for M < or = 5, or expanding polygonal chains of solitons for M > or = 6. In the conical geometry, these are concentric waves expanding in the radial direction.
Optics Letters 06/2010; 35(12):1974-6. · 3.40 Impact Factor
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ABSTRACT: Annularly and radially phase-modulated spatiotemporal necklace-shaped patterns (SNPs) in the complex Ginzburg-Landau (CGL) and complex Swift-Hohenberg (CSH) equations are theoretically studied. It is shown that the annularly phase-modulated SNPs, with a small initial radius of the necklace and modulation parameters, can evolve into stable fundamental or vortex solitons. To the radially phase-modulated SNPs, the modulated "beads" on the necklace rapidly vanish under strong dissipation in transmission, which may have potential application for optical switching in signal processing. A prediction that the SNPs with large initial radii keep necklace-ring shapes upon propagation is demonstrated by use of balance equations for energy and momentum. Differences between both models for the evolution of solitons are revealed.
Optics Express 08/2009; 17(15):12203-9. · 3.59 Impact Factor
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ABSTRACT: Mono-, di-, and tetranuclear Ru(II) polypyridine complexes based on the bridging ligand pdtp, where pdtp is 3-(pyridin-2-yl)-as-triazino[5,6-f]1,10-phenanthroline, have been synthesized and characterizated. This asymmetric bridging ligand is composed of two nonequivalent coordinating sites: one involves the phenanthroline moiety, and the other one involves the pyridyltriazine moiety. Electrochemical data show that the first redox process in these complexes is pdtp based and the metal-metal interaction in di- and tetranuclear complexes is very weak. The two oxidations (+1.41 and +1.56 V vs SCE) observed in dinuclear complex 2 are mainly ascribed to the different coordination environments of two metal centers. Absorption spectra are essentially the sum of the spectra of the component monometallic species. The emission spectra are measured both at room temperature and at 80 K in a 4:1 (v/v) EtOH/MeOH matrix. The complexes all display luminescence properties which are close to that featured by the parent [Ru(phen)(3)](2+) species. It is also noted that center-to-periphery energy transfer occurs in the dendritic tetranuclear complex 3.
Inorganic Chemistry 01/2004; 42(26):8823-30. · 4.60 Impact Factor
