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Detalhes

Detalhes

  • Nome

    Ariel Guerreiro
  • Cargo

    Responsável de Área
  • Desde

    01 maio 2007
002
Publicações

2023

A Multi-Plasmonic Approach for Simultaneous Measurements based on a D-Shaped Photonic Crystal Fiber Sensor: from Temperature to Optical Dispersion

Autores
Romeiro, F; Cardoso, P; Silva, O; Costa, CWA; Giraldi, MR; Santos, L; Baptista, M; Guerreiro, A;

Publicação
Journal of Microwaves, Optoelectronics and Electromagnetic Applications

Abstract
The growing demand for multiparameter sensors includes compact devices accompanied by simple calibration processes to distinguish the outputs from each other. This paper evaluates a scheme to determine multiple parameters of a medium using localized surface plasmon resonances (SPR) excited on a Dshaped photonic crystal fiber (PCF) partially covered by two gold layers of different thicknesses. We demonstrate that the proposed sensing platform, once customized to characterize the possible dispersive profiles of the refractive index of the analyte, also allows interrogating the temperature of a sample from a linear relationship. Since the plasmonic resonances are excited at separated and low crosstalk spectral channels, different sensing responses can be obtained simultaneously in the same location of the D-shaped PCF. These features turn out the SPR sensor a suitable tool for simultaneous monitoring of optical dispersion and temperature. © 2023 SBMO/SBMag.

2023

Exploring the hidden dimensions of an optical extreme learning machine

Autores
Silva, D; Ferreira, T; Moreira, FC; Rosa, CC; Guerreiro, A; Silva, NA;

Publicação
JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS

Abstract
Extreme Learning Machines (ELMs) are a versatile Machine Learning (ML) algorithm that features as the main advantage the possibility of a seamless implementation with physical systems. Yet, despite the success of the physical implementations of ELMs, there is still a lack of fundamental understanding in regard to their optical implementations. In this context, this work makes use of an optical complex media and wavefront shaping techniques to implement a versatile optical ELM playground to gain a deeper insight into these machines. In particular, we present experimental evidences on the correlation between the effective dimensionality of the hidden space and its generalization capability, thus bringing the inner workings of optical ELMs under a new light and opening paths toward future technological implementations of similar principles.

2023

Deep learning-based fully automatic segmentation of whole-body [18F]FDG PET/CT images from lymphoma patients: addition of CT data has poor impact on networks performance

Autores
Constantino, CS; Oliveira, FPM; Leocádio, S; Silva, M; Oliveira, C; Castanheira, JC; Silva, A; Vaz, S; Teixeira, R; Neves, M; Lúcio, P; Joao, C; Vinga, S; Costa, DC;

Publicação
EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING

Abstract

2022

Tunable Plasmonic Resonance Sensor Using a Metamaterial Film in a D-Shaped Photonic Crystal Fiber for Refractive Index Measurements

Autores
Cardoso, MP; Silva, AO; Romeiro, AF; Giraldi, MTR; Costa, JCWA; Santos, JL; Baptista, JM; Guerreiro, A;

Publicação
APPLIED SCIENCES-BASEL

Abstract
Subwavelength cells of metallic nanorods arrayed in a dielectric background, termed "metamaterials", present bulk properties that are useful to control and manipulate surface plasmon resonances. Such feature finds tremendous potential in providing a broad manifold of applications for plasmonic optical sensors. In this paper, we propose a surface-plasmon-resonance-based sensor with spectral response tunable by the volume fraction of silver present in a metamaterial layer deposited on a D-shaped photonic crystal fiber. Using computational simulations, we show that sensitivity and resolution can be hugely altered by changing the amount of constituents in the metamaterial, with no further modifications in the structure of the sensor. Moreover, the designed sensor can also be applied to label the average volume fraction of silver in the metamaterial layer and then to estimate its effective constitutive parameters.

2022

Nematic Liquid Crystals as a Tabletop Platform for Studying Turbulence

Autores
Ferreira, TD; Silva, NA; Guerreiro, A;

Publicação
U.Porto Journal of Engineering

Abstract
Light propagating in nonlinear optical materials opens the possibility to emulate quantum fluids of light with accessible tabletop experiments by taking advantage of the hydrodynamical interpretation. In this context, various optical materials have been studied in recent years, with nematic liquid crystals appearing as one of the most promising ones due to their controllable properties. Indeed, the application of an external electric field can tune their nonlocal response, and this mechanism may be useful for producing fluids of light and developing optical analogues. In this work, we extend the applicability of nematic liquid crystal to support optical analogues and study the possibility of emulating turbulent phenomena by using two fluids of light. These fluids interact with each other through the nonlinearity of the medium and generate instabilities that will lead to turbulent regimes. We also explore the possibility of exciting turbulent regimes through the decay of dark soliton stripes. The preliminary results are presented. © 2022, Universidade do Porto - Faculdade de Engenharia. All rights reserved.

Teses
supervisionadas

2022

Towards Realtime Classification of Optically Trapped Particles

Autor
Vicente Vieira Rocha

Instituição
UP-FCUP

2022

Optical Analogues: A Stepping Stone into Quantum Simulations and Computation

Autor
Tiago David da Silva Ferreira

Instituição
UP-FCUP

2022

Optical Extreme Learning Machines: a new trend in optical computing

Autor
Duarte José Fernandes da Silva

Instituição
UP-FEUP

2021

Light Quantum Properties and Applications: Secure Key Distribution Systems

Autor
Beatriz Gomes Soares

Instituição
UM

2021

Optical Analogues: A Stepping Stone into Quantum Simulations and Computation

Autor
Tiago David da Silva Ferreira

Instituição
UP-FCUP