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Publications

Publications by Pedro Jorge

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.

2022

Integrating Laser-induced breakdown spectroscopy and photogrammetry towards 3D element mapping

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

Publication
Journal of Physics: Conference Series

Abstract
The possibility to map the element distribution on a sample surface is one of the interesting applications of laser-induced breakdown spectroscopy that has been extensively explored in recent years. In this manuscript, we explore the combination of photogrammetry and LIBS techniques for the creation of a three-dimensional model of the map of the elements on the surface of the sample. Using a dedicated photogrammetry solution and software, we reconstruct the three-dimensional model of the mineral sample whose mesh is later exploited for the interactive interpretation of the results. Then, making use of Paraview software, which integrates production algorithms and computing performance in a unified solution for scientific purposes, we establish a process pipeline that allows the creation of an interactive three-dimensional model with the spatial distribution of the target elements on top of the sample surface. Our results demonstrate that combining these two techniques can give us a valuable resource for better qualitative analysis and insight, providing an innovative three-dimensional modeling solution that may open the door to a new range of possibilities, from quality control technology involving alloys and mechanical parts to interactive teaching environments for geo and biosciences, just to name a few examples. © Published under licence by IOP Publishing Ltd.

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