Navegando por Assunto "Nanoplasmônica"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Análise comparativa das propriedades ressonantes de nanopartículas e de nanoantenas bowtie de ouro de diferentes geometrias
(Universidade Federal do Pará, 2012-12-14) SANTOS, Thaís Lira Tavares dos; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647; DMITRIEV, Victor Alexandrovich; http://lattes.cnpq.br/3139536479960191
This work presents a comparative analysis of the resonant properties of gold nanoparticles and gold bowtie nanoantennas with new triangular geometries. The proposed geometries are as follows: the curved side triangular ones and the triangular geometries with one corner formed by three tips. The investigated properties are the resonant responses, the spatial distributions of the electric near-field and the resonant wavelengths. The current density inside the nanostructures is also analysed for better understanding of the electric near-field enhancement. For the case of bowtie nanoantennas, the research is also focused on the study of the influence of a silicon dioxide substrate on their resonant properties and on the study of their characteristics in the far-field region (scattering cross section and radiation pattern). The numerical results are obtained in the visible and near infrared regions of the electromagnetic spectrum, simulated by the finite integration technique. For isolated nanoparticles, these results show that the suggested geometries have electric near-field intensity around 160% higher and resonant wavelength redshifted by 15%, as compared to the equilateral triangular geometry. In the case of bowtie nanoantennas, the new geometries have electric near-field intensity 90% higher and resonant wavelength blueshifted by 15%, as compared to the triangular equilateral bowtie nanoantenna. The results of this work can serve for modeling, fabrication and designing of gold nanoparticles and gold bowtie nanoantennas for different applications, for example, microscopy and optical fibre sensors.
Acesso aberto (Open Access)
Análise de nanoenlaces ópticos sem fio compostos por nanoantenas plasmônicas yagi-uda e dipolo
(Universidade Federal do Pará, 2019-12-17) GARCIA, Tiago dos Santos; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
This work shows a comparative theoretical analysis of plasmonic nanoantennas Yagi-Uda and dipole wireless optical nanolinks. All results found from the isolated antennas at transmission mode such as, input impedance, directivity, gain, radiation efficiency, reflection coeficiente and radiation diagram were obtained by the linear Method of Moments, assitionally, the effect of a silicon dioxide substract on antenna resonant properties were obtained by the Finite Element Method through COMSOL Multiphysics software. The numerical analysis of the nanolink is performed by the linear Method of Moments, witch the transmission power and the near electric field are investigated and optimized for the nanolinks Yagi-Uda/Yagi-Uda, Yagi-Uda/dipole and dipole/dipole. The results show that the Yagi-Uda/Yagi-Uda nanolinks offers an improvement in power transmission at some frequency points over the nanolinks dipole/dipole and Yagi-Uda/dipole. In addition, the results demonstrate that all three links can operate at good transmit power at different frequency points, varying the load impedance of the receiving antenna.
Acesso aberto (Open Access)
Desenvolvimento de um algoritmo computacional MoM 3D aplicado em nanoplasmônica
(Universidade Federal do Pará, 2012-12-13) SOUZA, Nadson Welkson Pereira de; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
This work presents the development of a computational algorithm for electromagnetic scattering analysis of isolated plasmonic nanostructures. The tridimensional Method of Moments (MoM-3D) was used to solve the electric field integral equation, and the Lorentz-Drude model was used to represent the complex permittivity of the metallic nanostructures. Based in this model, a computational algorithm written in C language was developed. As example of application and validation of the code, two classical electromagnetic scattering problems of metallic nanoparticles are analyzed: nanosphere and rectangular nanorod, where the spectral response and near-field distributions were calculated. The obtained results were compared with other models and a good agreement and convergence was observed.
Acesso aberto (Open Access)
Development of computational 3D MoM algorithm for nanoplasmonics
(2013-12) SOUZA, Nadson Welkson Pereira de; COSTA, Karlo Queiroz da; DMITRIEV, Victor Alexandrovich
In this paper, we present an algorithm for full-wave electromagnetic analysis of nanoplasmonic structures. We use the three-dimensional Method of Moments to solve the electric field integral equation. The computational algorithm is developed in the language C. As examples of application of the code, the problems of scattering from a nanosphere and a rectangular nanorod are analyzed. The calculated characteristics are the near field distribution and the spectral response of these nanoparticles. The convergence of the method for different discretization sizes is also discussed.