1,720,961 research outputs found
Nonlocal spatial soliton interactions in nematic liquid crystals RID F-7127-2011
No full textThe interaction between spatial optical solitons in undoped nematic liquid crystals is governed by reorientational nonlinearity with a significant nonlocality. We demonstrate several cases of interactions, including crossing, interlacing, and merging of spatial solitons in voltage-biased liquid-crystal cells. A scalar model accounts for the main features that were experimentally observed. (C) 2002 Optical Society of America
Optically induced Zener tunneling in one-dimensional lattices
No full textWe investigate Landau-Zener tunneling in one-dimensional liquid crystalline waveguide arrays by all-optical impression of acceleration with an additional beam. We derive the Zener model from the governing equations and demonstrate a novel approach to Floquet-Bloch band tunneling. (c) 2006 Optical Society of America
Discrete light propagation and self-localization in voltage-controlled arrays of channel waveguides in undoped nematic liquid crystals
No full textWe review linear and nonlinear light propagation in a voltage-tunable liquid crystalline waveguide array. We report on discrete diffraction, discrete soliton generation, all-optical beam steering, multiband vector breathers and Bloch oscillations. The predictions, based on full numerical BPM simulations, are in excellent agreement with the experimental results
Discrete light propagation and self-trapping in liquid crystals
No full textWe investigate light propagation and self-localization in a voltage-controlled array of channel waveguides realized in undoped nematic liquid crystals. We report on discrete diffraction and solitons, as well as all-optical angular steering and the formation of multiband vector breathers. The results and are in excellent agreement with both coupled mode theory and full numerical simulations. (C) 2005 Optical Society of America
All-optical switching and beam steering in tunable waveguide arrays
No full textWe demonstrate all-optical switching by discrete beam steering in a voltage-controlled array of channel waveguides in nematic liquid crystals. The model keeps into account the reorientational response of the medium and are in agreement with the experimental data. (C) 2005 American Institute of Physics
Discrete propagation and spatial solitons in nematic liquid crystals
No full textWe investigate, for the first time to our knowledge, the discrete propagation of near-infrared light in a voltage-controlled array of channel waveguides in undoped nematic liquid crystals under planar anchoring conditions. This novel geometry enables us to drive the system from one-dimensional bulk diffraction to discrete propagation and, for larger excitations, to discrete spatial solitons, or nematicons.. The observed phenomena are adequately described by a, scalar model that encompasses the voltage-dependent reorientational response of the material. (C) 2004 Optical Society of America
Optical multiband vector breathers in tunable waveguide arrays
No full textWe investigate multiband optical breathers in a voltage-adjustable array of coupled waveguides in nematic liquid crystals. Symmetric breathers resulting from vector composition of modes from two bands are observed over large propagation distances and are described in terms of the Floquet-Bloch theory. (C) 2005 Optical Society of America
Nematic liquid crystal waveguide arrays
No full textWe investigate linear and nonlinear light propagation in a voltage-tunable array of waveguide channels in undoped nematic liquid crystals. This novel geometry, based on a photonic structure with a periodic modulation of refractive index controlled by air electric field, offers a wealth of possibilities for the study of discrete optical phenomena. The structure, in conjunction with a giant, non-resonant and voltage-dependent reorientational nonlinearity, allows us to drive the system from bulk diffraction to discrete propagation. Theoretical and experimental investigations, carried out with near infrared light wavelength and powers of a few milliWatts, show the possibility of transverse light localization, resulting in discrete spatial solitons. Such array, with its voltage- and light-adjustable guided-wave confinement and coupling, exhibits potentials for the realization of multifunctional routers and all-optical signal processors with nematic liquid crystals
Nonlinear wave propagation and spatial solitons in nematic liquid crystals RID F-7127-2011
No full textOptical spatial solitons have been demonstrated in bulk nematic liquid crystals. We present an overview of our recent experimental results on nonlinear wave propagation in nematic liquid crystals, focusing on spatial solitons through the reorientational nonlinear response. Various phenomena, including spatial readdressing, weak signal guiding and two-soliton interactions, are observed in voltage biased planar cells
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