Resumo Neste trabalho é apresentado um novo malhador para o MEF (Método de Elementos Finitos)... more Resumo Neste trabalho é apresentado um novo malhador para o MEF (Método de Elementos Finitos), chamado MeM (Malhador eletroMagnético). O MeM tem como objetivo gerar malhas para análise de problemas que utilizam o MEF, dentre os quais os de aplicações de microondas e optoeletrônica, que têm como característica uma grande diferença na dimensão do domínio exterior em relação às dos domínios interiores. O malhador é automático e adaptativo e possui uma interface amigável para o usuário. São apresentadas estatísticas da qualidade das malhas e resultados de aplicações em optoeletrônica. Palavras-chaves Geração de malhas, MEF, Malhas Adaptativas.
The various experimental sectors of physics in which superluminal motions seem to appear are brie... more The various experimental sectors of physics in which superluminal motions seem to appear are briefly mentioned. In particular, a bird's-eye view is presented of the experiments with evanescent waves (and/or tunneling photons) and with the "localized superluminal solutions" (SLS) to the wave equation, like the so-called X-shaped beams. The authors also present a series of new SLSs to the Maxwell equations, suitable for arbitrary frequencies and arbitrary bandwidths, some of them endowed with finite total energy. Among the others, the authors set forth an infinite family of generalizations of the classical X-shaped wave and show how to deal with the case of a dispersive medium. Results of this kind may find application in other fields in which an essential role is played by a wave equation (like acoustics, seismology, geophysics, gravitation, elementary particle physics, etc.).
In the present paper the analytical aspects related to the maximum invariance depth of propagatio... more In the present paper the analytical aspects related to the maximum invariance depth of propagation finite energy Airy-type beams are investigated, considering not only the usual exponentially dumped Airy beams but also the truncated ones. It is obtained an analytic expression which seems capable of finding accurately the maximum invariance distance of these waves. The results seem to be in line with those obtained from numerical simulations.
Proceedings of the 2003 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference - IMOC 2003. (Cat. No.03TH8678), 2003
... of Telaommunication$ Falrral Flumln-UNveniIy, Nitdi, Rio de Janeh, Brazil. ... [6] H. Masoudi... more ... of Telaommunication$ Falrral Flumln-UNveniIy, Nitdi, Rio de Janeh, Brazil. ... [6] H. Masoudi, A.Muhammad, Al-Sunaidi and A. Job, "Efficient Time-Domain BeamPropagation MetM far Modeling Optical Devices", IEEE/OsA Journal o/. Lightwave Technolow, Vol. ...
2006 International Telecommunications Symposium, 2006
A new and efficient spatio-temporal formulation based on the finite element method 2D is applied ... more A new and efficient spatio-temporal formulation based on the finite element method 2D is applied to simulate the propagation of optical ultra-short pulses in nonlinear media. The excellent performance of this technique in terms of the computational efficiency is demonstrated from its capacity to analyze simultaneously the propagation of the pulses in time domain and spatial domain. The new formulation
In this work we consider kink-antikink collisions for some classes of (1, 1)-dimensional nonlinea... more In this work we consider kink-antikink collisions for some classes of (1, 1)-dimensional nonlinear models. We are particularly interested to investigate in which aspect the presence of a general kinetic content in the Lagrangian could be revealed in a collision process. We consider a particular class of models known as twin theories, where different models lead to same solutions for the equations of motion and same energy density profile. The theories can be distinguished in the level of linear stability of defect structure. We study a class of k-defect theories depending on a parameter M which is the twin theory of the usual φ 4 theory with standard dynamics. For M → ∞ both models are characterized by the same potential. In the regime 1/M 2 << 1, we obtain analytically the spectrum of excitations around the kink solution. It is shown that with the increasing on the parameter 1/M 2 : i) the gap between the zero-mode and the first-excited mode increases and ii) the tendency of one-bounce collision between kink-antikink increases. We numerically investigate kink-antikink scattering, looking for the influence of the parameter changing for the thickness and number of two-bounce windows, and confronting the results with our analytical findings.
SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics, 2005., 2005
A new and efficient spatio-temporal formulation based on the finite element method 2D is applied ... more A new and efficient spatio-temporal formulation based on the finite element method 2D is applied to simulate optical devices with cylindrical symmetry. One spatial coordinate r, radial component, and one temporal coordinate τ, transversal component, constitute the discretization domain. The propagation occurs along z-direction, being incremented by Crank-Nicholson scheme. The finite-element in conjunction with Galerkin&#39;s method it&#39;s been applied to
... CA Dartora,1,* GG Cabrera,2 KZ Nobrega,3 VF Montagner,4 Marina HK Matielli,1 Fillipi Klos Rod... more ... CA Dartora,1,* GG Cabrera,2 KZ Nobrega,3 VF Montagner,4 Marina HK Matielli,1 Fillipi Klos Rodrigues de Campos,1 and Horacio Tertuliano S. Filho1 1Electrical Engineering Department, Federal University of Parana (UFPR), Brazil 2Institute of Physics Gleb Wataghin, State ...
In a previous paper we showed that localized superluminal solutions to the Maxwell equations exis... more In a previous paper we showed that localized superluminal solutions to the Maxwell equations exist, which propagate down ͑nonevanescence͒ regions of a metallic cylindrical waveguide. In this paper we construct analogous nondispersive waves propagating along coaxial cables. Such new solutions, in general, consist in trains of ͑undistorted͒ superluminal ''X-shaped'' pulses. Particular attention is paid to the construction of finite total energy solutions. Any results of this kind may find application in the other fields in which an essential role is played by a wave equation ͑like acoustics, geophysics, etc.͒.
ABSTRACT In this chapter a relatively new non-diffracting beam is reported: the Airy beam. Contra... more ABSTRACT In this chapter a relatively new non-diffracting beam is reported: the Airy beam. Contrasting to the well-known Bessel and Mathieu beams, the Airy beam is a solution of the wave equation only in the paraxial regime, but it has attracted much attention because of its ability to accelerate and bend during propagation, opening interesting possible applications in the field of optics. In this chapter, a brief introduction of finite-energy Airy beams is given, with an emphasis on analytical aspects related to the maximum invariance depth of propagation as well as reporting an analytic method for describing Airy-type beams truncated by finite apertures. Some commentary on applications of Airy pulses for optical communication.
SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics, 2005., 2005
ABSTRACT Chromatic dispersion engineering is one of the most promising advantages provided by the... more ABSTRACT Chromatic dispersion engineering is one of the most promising advantages provided by the photonic crystal fiber, PCFs. Their two-dimensional photonic crystal permits to manage the waveguide dispersion as a function of their design parameters: inter-hole spacing, hole diameter, number of air rings and cladding refractive index. Most PCFs are silica-based and has a honeycomb cladding. This paper presents a dispersion design methodology of high-index glass photonic crystal fibers, based on a new-geometry. Its numerical results point out positive or nearly zero ultra-flattened dispersion in a wide wavelength range. The nearly zero case presents chromatic dispersion at λ=1.55 μm equal to -0.352 ps/km/nm and a quite low slope equal to 1 · 10-3 ps/nm2/km at 1.5-1.6 μm window. The lowest obtained slope was 5 · 10-4 ps/nm2/km.
In this paper a theoretical study of the radiation pattern of an antenna build up from a confined... more In this paper a theoretical study of the radiation pattern of an antenna build up from a confined magnetoplasma is made. Assuming that the electron gas is in the linear regime, we derived expressions for the conductivity tensor of the plasma and the radiated electromagnetic field under the influence of both dc magnetic and ac electric externally applied fields. It is found that the radiation patterns are dependent on the relative orientations of the applied fields and in the frequency of the applied electric field.
It is now well known that Maxwell equations admit of wavelet-type solutions endowed with arbitrar... more It is now well known that Maxwell equations admit of wavelet-type solutions endowed with arbitrary group velocities (0Ͻv g Ͻϱ). Some of them, which are rigidly moving and have been called localized solutions, attracted large attention. In particular, much work has been done with regard to the superluminal localized solutions ͑SLSs͒, the most interesting of which are the ''X-shaped'' ones. The SLSs have been actually produced in a number of experiments, always by suitable interference of ordinary-speed waves. In this paper we show, by contrast, that even a superluminal charge creates an electromagnetic X-shaped wave: namely, on the basis of Maxwell equations, we are able to evaluate the field associated with a superluminal charge ͑under the approximation of pointlikeness͒: It results in constituting a very simple example of a true X wave.
Optik - International Journal for Light and Electron Optics, 2008
This paper presents PCFDT, which is an accurate and friendly photonic crystal fiber design tool b... more This paper presents PCFDT, which is an accurate and friendly photonic crystal fiber design tool based on fullvectorial finite element method. Photonic crystal fibers based on circular and non-circular microstructured holes, and on different propagation mechanisms have been analyzed. Comparisons with other numerical methods and experimental results have shown excellent agreement. The design tool validation includes experimental results of hybrid photonic crystal fibers, proposed by us, which made possible for the first time light be simultaneously confined and manipulated by two propagation mechanism, total internal reflection and photonic bandgap effect.
In this paper, we start from the well known DurninÕs experimental setup, finding general analytic... more In this paper, we start from the well known DurninÕs experimental setup, finding general analytical formulae to investigate generation and propagation of nondiffracting beams. Our general formula makes possible considering any kind of angular modulation. As an example we discuss the Mathieu beams. Moreover, in the study of Bessel beams we consider the width of the slit to compare with the ideal case represented by a Dirac d transmittance function.
In this paper, we present a generalization of the so-called Frozen Waves, which are new solutions... more In this paper, we present a generalization of the so-called Frozen Waves, which are new solutions to Maxwell's equations having the important characteristic of remaining static in space and keeping any previously chosen arbitrary longitudinal field pattern. In the pioneering work, these waves were introduced as a discrete superposition of zero-order Bessel beams. As a fact, here we will represent these waves as a continuous superposition of Bessel beams leading to a simpler and more compact mathematical formalism, which allows us to derive certain inequalities that restrict the physical properties of the Frozen Waves, such as their attainable longitudinal resolution. Besides this, we will discuss losses compensation in a lossy medium and, finally, their practical realization through finite apertures.
In this paper we analyze the effects of the time modulation of (zeroth-order) Bessel beams, by co... more In this paper we analyze the effects of the time modulation of (zeroth-order) Bessel beams, by considering a few different pulse shapes. Namely, three modulating functions are considered: a train of rectangular waves, a single rectangular pulse, and a gaussian pulse. The influence of the carrier frequency, and of shape and spectral bandwidth of the modulating function, is also discussed; while further support to our results is met by using the convolution technique in the time domain. At the beginning, a brief review of the X-shaped solutions to the wave equation, and of some properties of theirs, is presented.
This paper presents a study of a recent solution to Maxwell's equation, the so-called ''Frozen Wa... more This paper presents a study of a recent solution to Maxwell's equation, the so-called ''Frozen Waves'', whose main characteristics are to remain static in space, and to keep an arbitrary longitudinal field pattern previously chosen. These waves could be obtained by an adequate, but discrete, superposition of monochromatic Bessel beams. Contrary to that, we have here proposed a new way to get these waves through a continuous superposition of Bessel beams, and discussed some physical aspects and then exemplified for both loss and lossless media. r
Resumo Neste trabalho é apresentado um novo malhador para o MEF (Método de Elementos Finitos)... more Resumo Neste trabalho é apresentado um novo malhador para o MEF (Método de Elementos Finitos), chamado MeM (Malhador eletroMagnético). O MeM tem como objetivo gerar malhas para análise de problemas que utilizam o MEF, dentre os quais os de aplicações de microondas e optoeletrônica, que têm como característica uma grande diferença na dimensão do domínio exterior em relação às dos domínios interiores. O malhador é automático e adaptativo e possui uma interface amigável para o usuário. São apresentadas estatísticas da qualidade das malhas e resultados de aplicações em optoeletrônica. Palavras-chaves Geração de malhas, MEF, Malhas Adaptativas.
The various experimental sectors of physics in which superluminal motions seem to appear are brie... more The various experimental sectors of physics in which superluminal motions seem to appear are briefly mentioned. In particular, a bird's-eye view is presented of the experiments with evanescent waves (and/or tunneling photons) and with the "localized superluminal solutions" (SLS) to the wave equation, like the so-called X-shaped beams. The authors also present a series of new SLSs to the Maxwell equations, suitable for arbitrary frequencies and arbitrary bandwidths, some of them endowed with finite total energy. Among the others, the authors set forth an infinite family of generalizations of the classical X-shaped wave and show how to deal with the case of a dispersive medium. Results of this kind may find application in other fields in which an essential role is played by a wave equation (like acoustics, seismology, geophysics, gravitation, elementary particle physics, etc.).
In the present paper the analytical aspects related to the maximum invariance depth of propagatio... more In the present paper the analytical aspects related to the maximum invariance depth of propagation finite energy Airy-type beams are investigated, considering not only the usual exponentially dumped Airy beams but also the truncated ones. It is obtained an analytic expression which seems capable of finding accurately the maximum invariance distance of these waves. The results seem to be in line with those obtained from numerical simulations.
Proceedings of the 2003 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference - IMOC 2003. (Cat. No.03TH8678), 2003
... of Telaommunication$ Falrral Flumln-UNveniIy, Nitdi, Rio de Janeh, Brazil. ... [6] H. Masoudi... more ... of Telaommunication$ Falrral Flumln-UNveniIy, Nitdi, Rio de Janeh, Brazil. ... [6] H. Masoudi, A.Muhammad, Al-Sunaidi and A. Job, "Efficient Time-Domain BeamPropagation MetM far Modeling Optical Devices", IEEE/OsA Journal o/. Lightwave Technolow, Vol. ...
2006 International Telecommunications Symposium, 2006
A new and efficient spatio-temporal formulation based on the finite element method 2D is applied ... more A new and efficient spatio-temporal formulation based on the finite element method 2D is applied to simulate the propagation of optical ultra-short pulses in nonlinear media. The excellent performance of this technique in terms of the computational efficiency is demonstrated from its capacity to analyze simultaneously the propagation of the pulses in time domain and spatial domain. The new formulation
In this work we consider kink-antikink collisions for some classes of (1, 1)-dimensional nonlinea... more In this work we consider kink-antikink collisions for some classes of (1, 1)-dimensional nonlinear models. We are particularly interested to investigate in which aspect the presence of a general kinetic content in the Lagrangian could be revealed in a collision process. We consider a particular class of models known as twin theories, where different models lead to same solutions for the equations of motion and same energy density profile. The theories can be distinguished in the level of linear stability of defect structure. We study a class of k-defect theories depending on a parameter M which is the twin theory of the usual φ 4 theory with standard dynamics. For M → ∞ both models are characterized by the same potential. In the regime 1/M 2 << 1, we obtain analytically the spectrum of excitations around the kink solution. It is shown that with the increasing on the parameter 1/M 2 : i) the gap between the zero-mode and the first-excited mode increases and ii) the tendency of one-bounce collision between kink-antikink increases. We numerically investigate kink-antikink scattering, looking for the influence of the parameter changing for the thickness and number of two-bounce windows, and confronting the results with our analytical findings.
SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics, 2005., 2005
A new and efficient spatio-temporal formulation based on the finite element method 2D is applied ... more A new and efficient spatio-temporal formulation based on the finite element method 2D is applied to simulate optical devices with cylindrical symmetry. One spatial coordinate r, radial component, and one temporal coordinate τ, transversal component, constitute the discretization domain. The propagation occurs along z-direction, being incremented by Crank-Nicholson scheme. The finite-element in conjunction with Galerkin&#39;s method it&#39;s been applied to
... CA Dartora,1,* GG Cabrera,2 KZ Nobrega,3 VF Montagner,4 Marina HK Matielli,1 Fillipi Klos Rod... more ... CA Dartora,1,* GG Cabrera,2 KZ Nobrega,3 VF Montagner,4 Marina HK Matielli,1 Fillipi Klos Rodrigues de Campos,1 and Horacio Tertuliano S. Filho1 1Electrical Engineering Department, Federal University of Parana (UFPR), Brazil 2Institute of Physics Gleb Wataghin, State ...
In a previous paper we showed that localized superluminal solutions to the Maxwell equations exis... more In a previous paper we showed that localized superluminal solutions to the Maxwell equations exist, which propagate down ͑nonevanescence͒ regions of a metallic cylindrical waveguide. In this paper we construct analogous nondispersive waves propagating along coaxial cables. Such new solutions, in general, consist in trains of ͑undistorted͒ superluminal ''X-shaped'' pulses. Particular attention is paid to the construction of finite total energy solutions. Any results of this kind may find application in the other fields in which an essential role is played by a wave equation ͑like acoustics, geophysics, etc.͒.
ABSTRACT In this chapter a relatively new non-diffracting beam is reported: the Airy beam. Contra... more ABSTRACT In this chapter a relatively new non-diffracting beam is reported: the Airy beam. Contrasting to the well-known Bessel and Mathieu beams, the Airy beam is a solution of the wave equation only in the paraxial regime, but it has attracted much attention because of its ability to accelerate and bend during propagation, opening interesting possible applications in the field of optics. In this chapter, a brief introduction of finite-energy Airy beams is given, with an emphasis on analytical aspects related to the maximum invariance depth of propagation as well as reporting an analytic method for describing Airy-type beams truncated by finite apertures. Some commentary on applications of Airy pulses for optical communication.
SBMO/IEEE MTT-S International Conference on Microwave and Optoelectronics, 2005., 2005
ABSTRACT Chromatic dispersion engineering is one of the most promising advantages provided by the... more ABSTRACT Chromatic dispersion engineering is one of the most promising advantages provided by the photonic crystal fiber, PCFs. Their two-dimensional photonic crystal permits to manage the waveguide dispersion as a function of their design parameters: inter-hole spacing, hole diameter, number of air rings and cladding refractive index. Most PCFs are silica-based and has a honeycomb cladding. This paper presents a dispersion design methodology of high-index glass photonic crystal fibers, based on a new-geometry. Its numerical results point out positive or nearly zero ultra-flattened dispersion in a wide wavelength range. The nearly zero case presents chromatic dispersion at λ=1.55 μm equal to -0.352 ps/km/nm and a quite low slope equal to 1 · 10-3 ps/nm2/km at 1.5-1.6 μm window. The lowest obtained slope was 5 · 10-4 ps/nm2/km.
In this paper a theoretical study of the radiation pattern of an antenna build up from a confined... more In this paper a theoretical study of the radiation pattern of an antenna build up from a confined magnetoplasma is made. Assuming that the electron gas is in the linear regime, we derived expressions for the conductivity tensor of the plasma and the radiated electromagnetic field under the influence of both dc magnetic and ac electric externally applied fields. It is found that the radiation patterns are dependent on the relative orientations of the applied fields and in the frequency of the applied electric field.
It is now well known that Maxwell equations admit of wavelet-type solutions endowed with arbitrar... more It is now well known that Maxwell equations admit of wavelet-type solutions endowed with arbitrary group velocities (0Ͻv g Ͻϱ). Some of them, which are rigidly moving and have been called localized solutions, attracted large attention. In particular, much work has been done with regard to the superluminal localized solutions ͑SLSs͒, the most interesting of which are the ''X-shaped'' ones. The SLSs have been actually produced in a number of experiments, always by suitable interference of ordinary-speed waves. In this paper we show, by contrast, that even a superluminal charge creates an electromagnetic X-shaped wave: namely, on the basis of Maxwell equations, we are able to evaluate the field associated with a superluminal charge ͑under the approximation of pointlikeness͒: It results in constituting a very simple example of a true X wave.
Optik - International Journal for Light and Electron Optics, 2008
This paper presents PCFDT, which is an accurate and friendly photonic crystal fiber design tool b... more This paper presents PCFDT, which is an accurate and friendly photonic crystal fiber design tool based on fullvectorial finite element method. Photonic crystal fibers based on circular and non-circular microstructured holes, and on different propagation mechanisms have been analyzed. Comparisons with other numerical methods and experimental results have shown excellent agreement. The design tool validation includes experimental results of hybrid photonic crystal fibers, proposed by us, which made possible for the first time light be simultaneously confined and manipulated by two propagation mechanism, total internal reflection and photonic bandgap effect.
In this paper, we start from the well known DurninÕs experimental setup, finding general analytic... more In this paper, we start from the well known DurninÕs experimental setup, finding general analytical formulae to investigate generation and propagation of nondiffracting beams. Our general formula makes possible considering any kind of angular modulation. As an example we discuss the Mathieu beams. Moreover, in the study of Bessel beams we consider the width of the slit to compare with the ideal case represented by a Dirac d transmittance function.
In this paper, we present a generalization of the so-called Frozen Waves, which are new solutions... more In this paper, we present a generalization of the so-called Frozen Waves, which are new solutions to Maxwell's equations having the important characteristic of remaining static in space and keeping any previously chosen arbitrary longitudinal field pattern. In the pioneering work, these waves were introduced as a discrete superposition of zero-order Bessel beams. As a fact, here we will represent these waves as a continuous superposition of Bessel beams leading to a simpler and more compact mathematical formalism, which allows us to derive certain inequalities that restrict the physical properties of the Frozen Waves, such as their attainable longitudinal resolution. Besides this, we will discuss losses compensation in a lossy medium and, finally, their practical realization through finite apertures.
In this paper we analyze the effects of the time modulation of (zeroth-order) Bessel beams, by co... more In this paper we analyze the effects of the time modulation of (zeroth-order) Bessel beams, by considering a few different pulse shapes. Namely, three modulating functions are considered: a train of rectangular waves, a single rectangular pulse, and a gaussian pulse. The influence of the carrier frequency, and of shape and spectral bandwidth of the modulating function, is also discussed; while further support to our results is met by using the convolution technique in the time domain. At the beginning, a brief review of the X-shaped solutions to the wave equation, and of some properties of theirs, is presented.
This paper presents a study of a recent solution to Maxwell's equation, the so-called ''Frozen Wa... more This paper presents a study of a recent solution to Maxwell's equation, the so-called ''Frozen Waves'', whose main characteristics are to remain static in space, and to keep an arbitrary longitudinal field pattern previously chosen. These waves could be obtained by an adequate, but discrete, superposition of monochromatic Bessel beams. Contrary to that, we have here proposed a new way to get these waves through a continuous superposition of Bessel beams, and discussed some physical aspects and then exemplified for both loss and lossless media. r
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Papers by Kleber Nobrega