1,721,195 research outputs found
Parametric gap solitons in quadratic media
No full textLocalized energy states such as two-color gap solitons are theoretically and numerically predicted in a periodic structure in the presence of a frequency doubling nonlinearity. These parametric solitons exhibit appealing features as compared to the Kerr case. Novel erects such as merging and all-optical buffering are envisaged. (C) 1998 Optical Society of America
Integrated electro-optic switch in liquid crystals
No full textWe demonstrate a compact, low-power and broadband electrooptic switch in a simple waveguide geometry with undoped nematic liquid crystals. We experimentally achieve near infrared switching and signal routing with voltage modulations as low as 0.21V and a device length of 0.16mm. © 2005 Optical Society of America
Electro-optic routing in a nematic liquid-crystal waveguide
No full textWe propose a versatile guided-wave geometry encompassing electro-optic control for signal routing. A zero-gap directional coupler in liquid crystal can switch between two output states in the guide plane, permitting signal rerouting with modulation voltages as small as 70 mV. In the absence of an applied bias, no guiding - hence no modal output - is provided by the structure. © 2005 Optical Society of America
Distributed feedback grating in liquid crystal waveguide: a novel approach
No full textWe design a distributed feedback guided-wave device in liquid crystals, utilizing a simple geometry based on electro-optic molecular reorientation in uniaxial nematics. We numerically test the structure and demonstrate an effective Bragg reflector with voltage-tunable resonance. (C) 2009 Optical Society of Americ
Widely tunable electro-optic distributed Bragg reflector in liquid crystal waveguide
No full textWe propose and numerically investigate a versatile and easy-to-realize configuration for a guided-wave voltage-tunable distributed feedback grating based on reorientation in nematic liquid crystal and coplanar comb electrodes. The device has a wide tuning range exceeding 100 nm and covers C and L bands for wavelength division multiplexing. (C) 2010 Optical Society of Americ
Self-sustained trapping mechanism of zero-velocity parametric gap solitons
No full textUnder specific excitation conditions, slowly traveling parametric solitons in quadratic media with singly resonant Bragg gratings can evolve into zero-velocity localized solutions. We demonstrate numerically this phenomenon, providing physical insight in terms of momentum densities
Complex dynamics and configurational entropy of spatial optical solitons in nonlocal media RID F-7127-2011
No full textIntense light propagating in a nonlinear medium can generate an ensemble of interacting filaments of light, or spatial solitons. Using nematic liquid crystals, we demonstrate that the filaments exhibit collective behavior typical of complex systems, including the formation of clusters and soundlike vibrations, as well as the reduction of the configurational entropy, controlled by the degree of nonlocality of the medium. (c) 2006 Optical Society of America
Highly non-local optical solitons and their observation in nematic liquid crystals
No full textWe investigate 2-dimensional spatial optical solitons in media exhibiting a large nonlocal response coupled with a self-focusing nonlinearity. To this extent, with reference to a specific system in undoped nematic liquid crystals, we develop a general theory of spatial solitons in media with an arbitrary degree of nonlocality and carry out experimental observations to validate the model. The remarkable agreement between predictions and data yields evidence of narrow-waist solitons, revealing an important connection between nonparaxiality and nonlocality and emphasizing the role of nonlocality
EXCITATION OF SELF-TRANSPARENCY BRAGG SOLITONS IN QUADRATIC MEDIA
No full textWe show that self-transparent or gap solitons with leading-order components at fundamental frequency can be generated in a singly resonant Bragg grating by second-harmonic generation. We discuss the conditions required for exciting these localized waves. (C) 1997 Optical Society of America
Trapping of slowly-moving or stationary two-color gap solitons
No full textWe address the important problem of excitation of gap solitons of a parametric nature, which are sustained in periodically corrugated frequency-doubling media near Bragg resonance with both the fundamental frequency and its second harmonic. We demonstrate that a zero-velocity soliton can be trapped in a finite Bragg structure by the quiescence of two counterpropagating moving solitons, which in turn might be formed by injection of appropriate light pulses at a single carrier frequency
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