1,721,153 research outputs found
Three-dimensional superprism effect in photonic-crystal slabs
No full textThis paper presents a numerical study of the super-prism effect in photonic-crystal (PC) slabs. A fully vectorial three-dimensional time-domain code allows to simulate, with virtually no approximations, the role of the sample finiteness in the dispersive response of the frequency-banded structure. Out-of-plane coupling and transmission of, the device are investigated
Light-confinement, accessible spatial solitons and their interactions via nonlocal reorientation in nematic liquid crystals
No full textPhotonic crystal wires for optical parametric oscillators in isotropic media
No full textWe investigate four wave mixing in photonic crystal wire microresonators realized in an isotropic medium. One-dimensional optical parametric oscillators are numerically analyzed by solving Maxwell's equations in all dimensions and including material dispersion as well as nonlinear polarization
Parametric oscillations in photonic crystal slabs 3-D time-domain analysis
No full textSlab waveguides with a two-dimensional periodic distribution of the refractive index are proposed and investigated as optical microcavities for efficient parametric oscillations through four-wave mixing in isotropic materials. We carry out a case study based on the complete solution of three-dimensional Maxwell equations, including material dispersion and cubic nonlinear response
Integrated Bragg reflectors in low-index media: enabling strategies for wavelength tunability in electro-optic liquid crystals
No full textThis paper reports two configurations of Bragg reflectors based on liquid crystals confined between two small glass plates. Both approaches employ the efficient electro-optic effect in liquid crystals, which allows tunability of the reflectors by using low voltages. The molecular reorientation induced by an applied electric field implies a refractive index modulation seen by polarized light propagating into the liquid crystal. We show design criteria and profile optimization of the electrodes to induce a liquid crystal refractive index periodic modulation, providing a wavelength selective propagation of confined light in the liquid crystal. The two proposed device configurations differ for the top-bottom electrode configuration in one case and coplanar electrodes in the other case. Modeling of both configurations has been carried by calculating the applied electric field distribution and its interaction with the liquid crystal elastic properties taking into account the boundary conditions due to the alignment layer on the inner faces of the glass substrates. The calculated performance in terms of high wavelength selectivity and ultrawide spectral tuning range indicate that the two designed structures can be proposed for both optical filtering and to produce novel low power integrated distributed feedback resonators in dense wavelength division multiplexed fiber optic systems. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3559210
Low Power All Optical Rectangular Liquid Crystal Waveguide
No full textAll-optical control of a polymer rectangular waveguide with liquid crystal core is theoretically investigated. Light propagation is established with low input power control, that excites optical nonlinearity due to optically induced reorientational effect
Efficient frequency doubling in Reverse Proton Exchanged lithium niobate waveguides
No full textWe propose a novel approach for efficient frequency doubling of near infrared light, using the coupled system of buried and surface waveguides obtainable by Reverse Proton Exchange in z-cut lithium niobate. In such guides, supporting TM and TE polarizations, respectively, in spite of the use of the d31 nonlinear element, we predict conversion efficiencies as high as 90 % or 14 % μm/W cm in planar structures excited at 1.32 μm
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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