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Publications

Publications by Pedro Jorge

2020

Off-axis Fiber Bragg Grating Fabricated by Femtosecond Laser Direct Writing for Torsion Sensing

Authors
Viveiros, D; De Almeida, JMMM; Coelho, L; Maia, JM; Amorim, VA; Jorge, PAS; Marques, PVS;

Publication
Optics InfoBase Conference Papers

Abstract
The precise production of 4.5 µm off-axis first order FBG in an SMF-28e fiber through femtosecond laser direct writing is demonstrated. The off-axis FBG potential as sensing head for torsion sensing was successfully explored. © 2021 The Author(s).

2020

Characterization of Femtosecond Laser Direct Written Mach-Zehnder Interferometers Based on Titanium Dioxide Coated Long Period Fiber Gratings

Authors
Viveiros, D; Vasconcelos, H; De Almeida, JMMM; Coelho, L; Amorim, VA; Maia, JM; Jorge, PAS; Marques, PVS;

Publication
Optics InfoBase Conference Papers

Abstract
Optical fiber Mach-Zehnder interferometers were fabricated by combining two TiO2 coated LPFGs fabricated through femtosecond laser direct writing. Results of its refractometric characterization are presented and compared with the single LPFGs sensors. Wavelength sensitivity of 1175 nm/RIU at 1.38 and spectral resolution of 2.2×10-5 were achieved. © 2021 The Author(s).

2022

Optical Fiber Sensor for the Detection of Decarboxylation Products of Amino Acids

Authors
Vasconcelos, H; De Almeida, JMMM; Mendes, J; Dias, B; Jorge, PAS; Saraiva, C; Coelho, LCC;

Publication
Optics InfoBase Conference Papers

Abstract
Long period fiber gratings coated with TiO2 and poly(ethylene-co-vinyl acetate) (PEVA), a polymeric structure permeable biogenic amines found in foodstuff, were used to detect these compounds through the wavelength shift of its attenuation band. © 2022 The Author(s).

2022

Intelligent Optical Tweezers with deep neural network classifiers

Authors
Rocha, V; Oliveira, J; Guerreiro, A; Jorge, PAS; Silva, NA;

Publication
EPJ Web of Conferences

Abstract
Optical tweezers use light to trap and manipulate mesoscopic scaled particles with high precision making them a useful tool in a plethora of natural sciences, with emphasis on biological applications. In principle, the Brownian-like dynamics reflect trapped particle properties making it a robust source of information. In this work, we exploit this information by plotting histogram based images of 250ms of position or displacement used as input to a Convolution Neural Network. Results of 2-fold stratified cross-validation show satisfying classifications between sizes or types of particles: Polystyrene and Polymethilmethacrylate thus highlighting the potential of CNN approaches in faster and non-invasive applications in intelligent opto and microfluidic devices using optical trapping tools.

2022

Listening plasmas in Laser-Induced Breakdown Spectroscopy

Authors
Cavaco, R; Rodrigues, P; Lopes, T; Capela, D; Ferreira, MFS; Jorge, PAS; Silva, NA;

Publication
Journal of Physics: Conference Series

Abstract
Apart from radiation, which constitutes the primary source of information in laser-induced breakdown spectroscopy, the process is accompanied by secondary processes such as shock wave generation and sound emission. In this manuscript, we explore the possibility of relating plasma properties with the sound from the shock waves in multiple materials, from metals to minerals. By analyzing the behavior of shock wave sound from homogeneous reference metallic targets, we investigate the relation between plasma properties and sound signal, demonstrating that distinct materials and plasma characteristics correspond to distinct plasma sound fingerprints. © Published under licence by IOP Publishing Ltd.

2022

Multimodal approach to mineral identification: Merging Laser-induced breakdown spectroscopy with Hyperspectral imaging

Authors
Lopes, T; Cavaco, R; Rodrigues, P; Ferreira, J; Capela, D; Ferreira, MFS; Jorge, PAS; Silva, NA;

Publication
Journal of Physics: Conference Series

Abstract
While laser-induced breakdown spectroscopy is often used as a standalone technique, recent years saw an increasing interest in their combination with additional techniques towards multimodal sensing solutions capable of enhancing the capabilities of this technological solution. In this work, we try to identify possible synergies that arise from merging the analysis of laser-induced breakdown spectroscopy with that from a hyperspectral scanning of the sample, comparing it with the performance of standalone solutions. Having investigated the multimodal approach for a case study involving the identification of lithium minerals, our preliminary results demonstrate that while both solutions can provide reasonable results for qualitative mineral identification, they feature advantages and disadvantages that shall be taken into further consideration. Nevertheless, when working in collaboration, the results enclosed suggest that an integrated tandem solution can be an interesting tool for material analysis for research and industrial applications, combining the best of both instruments. © Published under licence by IOP Publishing Ltd.

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