A new three-dimensional (3-D) full-vectorial finite-difference (FD)-based beam-propagation method (BPM) is introduced for the analysis of magnetooptic and nonlinear materials. The refractive-index growth in the nonlinear material is allowed to saturate at high optical power densities (cubic-quintic media). The new formalism is capable of handling any combination of linear, nonlinear, and magnetooptic media, and combines, for the first time, the alternating-direction implicit technique (to improve computational performance) with the leapfrog longitudinal scheme (to simplify the solution of the coupled equations for transverse field components). The result is a numerical method that is both computationally efficient and numerically robust. The proposed BPM formalism is applied to investigate a (nonreciprocal) magnetooptic rib waveguide, as well as the new striking phenomena of light condensates propagation in cubic-quintic (saturable) media, the dynamics of which resemble those of liquid droplets.

Resumo Neste trabalho foi desenvolvido um software que prediz a variação de direção de incidência dos raios solares ao longo do ano e dos horários do dia, o qual é utilizado para estimar a melhor orientação na instalação de painéis fotovoltaicos na cidade de Belém/PA. A utilização do potencial de radiação solar em Belém poderá ser transformada em energia útil. Todavia, a eficiência de conversão solar no local também depende das condições atmosféricas que interferem nesse aproveitamento. Portanto, também foram avaliados os efeitos de tempo nublado e chuvoso através da precipitação e da comparação entre a radiação simulada (para céu limpo) e a radiação medida disponibilizada pelo INMET, que estima a radiação real, o que leva em conta efeitos que afetam a radiação, como céu nublado. Portanto, a partir da análise conjunta da radiação solar incidente na superfície com o índice pluviométrico, foi avaliada a potencialidade energética solar do local durante o ano, onde foi possível perceber uma correlação do período de menor precipitação com a elevação no índice de radiação medido, favorecendo nesse período um melhor rendimento energético para o painel fotovoltaico.

The design of a new multifunctional integrated optical device capable of operating simultaneously as an optical switch and optical isolator is presented. The device consists of a multilayer directional coupler employing one nonlinear and one magneto-optic layer, with all other layers being linear and isotropic. Therefore, only phase matching conditions are required for the device operation irrespective of the propagation directions and operation regime (linear∕nonlinear). The structure is optimized via a genetic algorithm and tested with a numerical formalism based on the wide-angle finite-difference beam propagation method. The results clearly demonstrate the ability of performing two distinct functions on the same device.

We present a synergistic investigation into ozone production dynamics within a high-voltage reaction chamber operating from 1.75 kV to 10 kV, at 60 Hz. The output ozone concentration dependence on a 60 Hz root mean square high-voltage for an air input pressure of 0.1 bar was measured using an ultraviolet-based sensor. A finite-element numerical model of the reaction chamber was developed and used for obtaining the reaction rate for the generated ozone for each level of input voltage and the internal distribution of the gas vector velocity field and ozone concentration. An expression to estimate the ozone reaction rates from the measured ozone concentrations was also derived. It was then compared and validated using the developed computational model. Therefore, in this work, a formula is proposed to estimate the ozone production by providing the experimental reaction rates. The other objective is to analyze the hysteresis phenomena observed in the partial discharges’ levels in the reaction chamber and in the output ozone concentration. Finally, we establish a connection between the total power of partial discharges and the consequent ozone production, clarifying the role of cumulative partial discharges’ power levels in governing the resultant output ozone concentration.

Current density distribution in optical ground wire cables hit by lightning strokes is numerically calculated and studied in time domain. For this analysis, two models for current source were considered, since atmospheric discharge has two major components which usually damage more severely the cable: the long and short duration current components. The analysis is performed by employing the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method, which the presented formulation was especially developed by the authors to analyze this phenomenon. The convolutional perfectly matched layer (CPML) technique adapted for the ADI method, called ADI-CPML, is also developed in this work for truncating the ADI-FDTD computational domain.

An unconditionally stable finite-difference time-domain (FDTD) scheme, which employs a similar technique to the alternating direction implicit (ADI), is proposed to study the electromagnetic wave propagation in bi-isotropic media. In the proposed scheme, the unidimensional Maxwell's equations in the time domain for bi-isotropic media were solved numerically. All transversal field components were included in the formalism to properly account special phenomena that may occur, such as polarization rotation and nonorthogonality between the electric and magnetic fields. The presented results are focused on chiral media.