Two-color discrete localized modes and resonant scattering in arrays of nonlinear quadratic optical waveguides

We analyze the properties and stability of two-color discrete localized modes in arrays of channel waveguides where tunable quadratic nonlinearity is introduced as a nonlinear defect by periodic poling of a single waveguide in the array. We show that, depending on the value of the phase mismatch and the input power, such two-color defect modes can be realized in three different localized states. We also study resonant light scattering in the arrays with the defect waveguide.Comment: 10 pages, 3 figures, published in PR

Fano resonance in quadratic waveguide arrays

We study resonant light scattering in arrays of channel optical waveguides where tunable quadratic nonlinearity is introduced as nonlinear defects by periodic poling of single (or several) waveguides in the array. We describe novel features of wave scattering that can be observed in this structure and show that it is a good candidate for the first observation of Fano resonance in nonlinear optics.Comment: 3 pages, 3 figures, submitted to Optics Letters, slightly revise

BALANCING WORK AND STUDIES: THE OMANI STUDENTS’ PERSPECTIVE

The study was conducted to describe the demographics of the working students and their work and study conditions; it also determined the relationship of the former to the latter. A total of one- hundred twenty-eight students from one private higher education institution (HEI) in the Sultanate of Oman participated in the study. The study adopted a quantitative method of research. The instrument which was designed by the researchers had high internal consistency and was validated by a group of researchers. Likert scaling was used to describe the conditions while frequency, mean, standard deviation were used to analyse the data. The relationship was tested through Pearson r. The findings revealed that majority of the respondents are young learners. Almost half are married; while majority are male; respondents were almost equally distributed in terms of private and government employment while a few have their own business. In regard to work and study conditions, three items were strongly agreed while only one was strongly disagreed; five items were agreed and another item was disagreed. As to relationship, respondents’ age, nature of employment, and study level were seen to have significant relationship with some of the work and study factors while marital status and gender were not found to have relationship. The findings in this study could be a starting point to obtain some relevant information about the conditions of students who are working while studying especially in the Sultanate; given that there is limited state—of the-art literature in terms of this research endeavour. The future study could be conducted involving a higher number of education institutions so to gather more pertinent information.  Article visualizations

Spatial rogue waves in photorefractive SBN crystals

We report on the excitation of large-amplitude waves, with a probability of around 1% of total peaks, on a photorefractive SBN crystal by using a simple experimental setup at room temperature. We excite the system using a narrow Gaussian beam and observe different dynamical regimes tailored by the value and time rate of an applied voltage. We identify two main dynamical regimes: a caustic one for energy spreading and a speckling one for peak emergence. Our observations are well described by a two-dimensional Schr\"odinger model with saturable local nonlinearity.Comment: 4 pages, 4 figure

La imagen de los candidatos a la presidencia de México en la prensa de Guadalajara durante el proceso electoral federal de 2012

La cobertura y tratamiento que los cuatro diarios de mayor circulación en la ciudad de Guadalajara dieron a los candidatos a la Presidencia de la República durante la contienda electoral federal de 2012 fue marginal y no equitativo. El espacio dedicado a notas sobre los candidatos fue, en todos los casos, menor al 8%; no se expusieron con suficiente amplitud las propuestas de campaña y se centraron en los temas de política partidista y las incidencias de las campañas mismas. Los datos muestran que, con un alto grado de correlación, El Informador y Milenio Jalisco favorecieron al candidato del Partido Revolucionario Institucional mientras que Mural y La Jornada Jalisco favorecieron al candidato del Partido de la Revolución Democrática.ITESO, A.C

Nonlinear localized modes in dipolar Bose-Einstein condensates in optical lattices

The modulational instability and discrete matter wave solitons in dipolar BEC, loaded into a deep optical lattice, are investigated analytically and numerically. The process of modulational instability of nonlinear plane matter waves in a dipolar nonlinear lattice is studied and the regions of instability are established. The existence and stability of bulk discrete solitons are analyzed analytically and confirmed by numerical simulations. In a marked contrast with the usual DNLS behavior (no dipolar interactions), we found a region where the two fundamental modes are simultaneously unstable allowing enhanced mobility across the lattice for large norm values. To study the existence and properties of surface discrete solitons, an analysis of the dimer configuration is performed. The properties of symmetric and antisymmetric modes including the stability diagrams and bifurcations are investigated in closed form. For the case of a bulk medium, properties of fundamental on-site and inter-site localized modes are analyzed. On-site and inter-site surface localized modes are studied finding that they do not exist when nonlocal interactions predominate with respect to local ones.Comment: 12 pages, 13 figure

Surface gap solitons at fabricated photonic lattice interfaces

We generate surface gap solitons with staggered phase structure at the edge of a semi-infinite LiNbO3 waveguide array with defocusing nonlinearity. We characterize self- localization dynamics and identify the threshold power for soliton formation