Gilliard N. Malheiros-Silveira

Dielectric resonator antenna for applications in nanophotonics

Optical nanoantennas, especially of the dipole type, have been theoretically and experimentally demonstrated by many research groups. Likewise, the plasmonic waveguides and optical circuits have experienced significant advances. In radio frequencies and microwaves a category of antenna known as dielectric resonator antenna (DRA), whose radiant element is a dielectric resonator (DR), has been designed for several applications, including satellite and radar systems. In this letter, we explore the possibilities and advantages to design nano DRAs (NDRAs), i. e., DRAs for nanophotonics applications. Numerical demonstrations showing the fundamental antenna parameters for a circular cylindrical NDRA type have been carried out for the short (S), conventional (C), and long (L) bands of the optical communication spectrum.

Strategy of Search and Refinement by GA in 2-D Photonic Crystals With Absolute PBG

The finite element method (FEM) and the genetic algorithm (GA) have been used to solve the inverse problem involving absolute photonic band gap (PBG) searching and optimization. Square and triangular lattices composed by Tellurium (anisotropic material) and air have been analyzed. In order to avoid the requirements of high computational efforts and resources needed in these kind of tasks, the PBGs have been computed only at key positions along the first region of Brillouin and we obtained absolute midgap ratio, considering PBGs between the TE 1-2 and TM 3-4 modes, of 18.00% and 23.49% for the square and triangular lattices, respectively.

Breakthroughs in Photonics 2013: Advances in Nanoantennas

The field of nanoantennas overlaps several areas of scientific interest, from fundamental physics to commercial technologies. Advances in the understanding of such complex devices hold the promises to novel applications in sensing, telecommunications, optical processing, and security, among others. Here, we review the main advances in the field of nanoantennas in 2013, from single metallic and dielectric devices to nanostructured metasurfaces and phased arrays.

Site-Controlled Growth of Monolithic InGaAs/InP Quantum Well Nanopillar Lasers on Silicon

In this Letter, we report the site-controlled growth of InP nanolasers on a silicon substrate with patterned SiO2 nanomasks by low-temperature metal-organic chemical vapor deposition, compatible with silicon complementary metal-oxide-semiconductor (CMOS) post-processing. A two-step growth procedure is presented to achieve smooth wurtzite faceting of vertical nanopillars. By incorporating InGaAs multiquantum wells, the nanopillar emission can be tuned over a wide spectral range. Enhanced quality factors of the intrinsic InP nanopillar cavities promote lasing at 0.87 and 1.21 μm, located within two important optical telecommunication bands. This is the first demonstration of a site-controlled III-V nanolaser monolithically integrated on silicon with a silicon-transparent emission wavelength, paving the way for energy-efficient on-chip optical links at typical telecommunication wavelengths.

Dielectric Resonator Nanoantenna Coupled to Metallic Coplanar Waveguide

A proposal about a dielectric resonator nanoantenna applied to couple optical beams to a surface plasmon coplanar waveguide (SP CPW), and vice versa, was theoretically investigated. The effects of this device operating in optical frequencies were studied, taking into account the central frequency of the conventional optical communication spectrum (C-band). Numerical results show that this proposal is interesting in that it couples an optical beam with an SP CPW with a good reflection coefficient, gain, and broadside radiation pattern.

Maximizing complete band gaps in two-dimensional photonic crystals by using artificial immune network

In this manuscript, an artificial immune network was applied to the inverse problem of maximization of complete photonic band gaps in two-dimensional photonic crystals. The computation of dispersion relations in such structures were carried out by means of the MIT Photonic-Bands package. Because of its multimodal searching capability, the artificial immune network could reach similar results, as well as improved ones, when compared to a similar approach based on genetic optimization.

GPW excited by folded dipole antenna with opened loop

We have modeled an alternative way of exciting a gap plasmonic waveguide by a folded dipole nanoantenna with an opened loop. The gain performance is around 62% the one obtained by a conventional dipole.

Improving dispersion compensation of photonic crystal fibers through air hole core insertion

The analysis of the insertion of one air hole centered in the core region of a Dispersion Compensating Photonic Crystal Fiber (DCPCF) was done by numerical modeling via Finite Element Method (FEM). A case study of this kind of optical fiber was evaluated. Based on this study, it was observed that the simple insertion of the air hole in the central region of the DCPCF and the variation of its diameter can produce significant improvements in fibers designed for this purpose.

Dielectric resonator nanoantenna array for optical frequencies

A dielectric resonator nanoantenna array is numerically investigated. The study was carried out by using the FIT- finite integration technique. The results show a promising alternative for coupling external beams to plasmonic waveguides.

Novel monopole antenna for Bluetooth and UWB applications

A compact monopole planar integrated antenna, with low profile, low cost and small size is proposed for Bluetooth and Ultrawideband (UWB) applications. Theoretical analyses were carried out using the commercial electromagnetic simulator software HFSS™. The antenna covers the operation frequencies, at least, from 2.352 GHz to 11 GHz and is designed on FR4 substrate.