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Sobre

Sobre

Paulo Marques nasceu em Coruche, Portugal, em 1968. Licenciou-se em Física em 1991, concluiu o mestrado em Optoelectrónica e Lasers em 1995 e doutorou-se em Física em 2000 (todos os graus pela Universidade do Porto); é Professor Auxiliar no Departamento de Física e Astronomia da Faculdade de Ciências da Universidade do Porto desde 2002.

Desde Julho de 2000 que desenvolve a sua actividade de investigação no INESC Porto, onde tem sido responsável por diversos projetos nacionais e internacionais. Os seus interesses situam-se nos domínios da óptica guiada e microfabricação (guias de onda , sensores ópticos, fotosensibilidade, processos de escrita direta a laser com impulsos ultracurtos, etc). Publicou 33 patentes das quais 32 são internacionais, mais de 100 artigos em revistas e conferências internacionais e dois capítulos de livros. Desde Outubro de 2009 é o Coordenador do Centro de Fotónica Aplicada do INESCTEC e desde Maio de 2013 é também o Coordenador da Unidade de Micro e Nanofabricação (MNTEC) do Centro de Materiais da Univerisdade do Porto (CEMUP).

Detalhes

Detalhes

013
Publicações

2022

Femtosecond laser micromachining of suspended silica-core liquid-cladding waveguides inside a microfluidic channel

Autores
Maia, JM; Viveiros, D; Amorim, VA; Marques, PVS;

Publicação
OPTICS AND LASERS IN ENGINEERING

Abstract
This work addresses the fabrication of straight silica-core liquid-cladding suspended waveguides inside a microfluidic channel through fs-laser micromachining. These structures enable the reconfiguration of the waveguide's mode profile and enhance the evanescent interaction between light and analyte. Further, their geometry resembles a tapered optical fiber with the added advantage of being monolithically integrated within a microfluidic platform. The fabrication process includes an additional post-processing thermal treatment responsible for smoothening the waveguide surface and reshaping it into a circular cross-section. Suspended waveguides with a minimum core diameter of 3.8 µm were fabricated. Their insertion losses can be tuned and are mainly affected by mode mismatch between the coupling and suspended waveguides. The transmission spectrum was studied and it was numerically confirmed that it consists of interference between the guided LP01 mode and uncoupled light and of modal interference between the LP01 and LP02 modes. © 2022 Elsevier Ltd

2022

The effect of frequency modulation on the FSR of a Fabry-Perot cavity using an Optical Spectrum Analyser

Autores
Reis, J; V.Rodrigues, A; Robalinho, P; Novais, S; Maia, J; Marques, P; Roma, D; Salvans, J; Canal, M; Ramos, J; Gualani, V; Sisteré, S; Martín, V; Nofrarias, M; Silva, S; Frazão, O;

Publicação
EPJ Web of Conferences

Abstract
It is presented a study of the dependence between the free spectral range (FSR) and the cavity length in Fabry-Perot interferometers. Furthermore, the effect of frequency modulation on the FSR is studied when an optical spectrum analyser (OSA) is used as an interrogator. For low frequency range it is possible to observe this behaviour in the OSA and using an appropriate processing signal it is possible to use the white light interferometry technique.

2021

Mach-Zehnder interferometer-based evanescent refractometer inscribed at the surface of Eagle2000 by femtosecond laser writing

Autores
Amorim, VA; Maia, JM; Viveiros, D; Marques, PVS;

Publicação
IEEE SENSORS JOURNAL

Abstract

2021

Intensity-modulated refractometer based on mode-mismatch in surface waveguides inscribed by femtosecond laser direct writing

Autores
Amorim, VA; Viveiros, D; Maia, JM; Marques, PVS;

Publicação
OPTICS AND LASER TECHNOLOGY

Abstract
Optical waveguides were fabricated at the surface of Eagle2000 glass substrates, using femtosecond laser direct writing and wet etching, and their potential as intensity-modulated refractometers was assessed. Through the analysis of their broadband spectral response to different refractive index oils, we observed that mode mismatch is present when the guided mode reaches the surface of the substrate and interacts with the external medium, thus enabling the use of such optical waveguides in refractive index sensing. Refractive indices equal to or greater than that of the substrate also induced a coupling mechanism that was shown not to be suitable in these devices. The device's wavelength of operation was found to be tunable by controlling the distance between the surface and the center of the optical waveguide. However, the sensitivity was seen to diminish by increasing the latter, being nonexistent for distances greater than 5.5 mu m. In this study, the maximum sensitivity values were found for a surface to core center distance between 1 and 2 mu m, in the biological range, and 2.5 to 3 mu m, for a refractive index nearing that of the substrate. Accordingly, maximum sensitivities of approximate to 25 dB/RIU and approximate to 1200 dB/RIU were found between 1.300 < n(D)(25)degrees(C) < 1.400 and 1.490 < n(D)(25)degrees(C) < 1.500, respectively.

2021

Loss mechanisms in femtosecond laser written optical waveguides

Autores
Marques, PVS; Amorim, VA; Maia, JM; Viveiros, D;

Publicação
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
Low loss optical waveguides are the key component for the fabrication of more complex integrated optics devices. In most works related to femtosecond laser written waveguides, the values presented give results at a single wavelength or in a narrow wavelength band; but some applications in optical sensing, for example, would benefit from waveguides having good propagation properties in a larger wavelength range. This paper presents results that allow one to gain insight into the major loss mechanisms present in laser written waveguides in two different types of glasses (fused silica and Eagle 2000 glass) and the dependence of those on the fabrication parameters. Finally, an example of application of broadband operating waveguides is given.

Teses
supervisionadas

2020

Fast prototyping of advanced sensing devices using three-dimensional direct writing with femtosecond laser

Autor
Vítor Alexandre Oliveira Amorim

Instituição
UP-FCUP

2020

Fabricação de nanoestruturas por fotopolimerização multifotão com laser femtosegundo

Autor
José Miguel Trigo de Mesquita e Silva

Instituição
UP-FCUP

2020

Fabrication of opticals Ensing devices by 3D laser  micromachining

Autor
Carlos Duarte Rodrigues Viveiros

Instituição
UP-FCUP

2019

Fabrication of opticals Ensing devices by 3D laser micromachining

Autor
Carlos Duarte Rodrigues Viveiros

Instituição
UP-FCUP

2019

Optical fibre tweezers for trapping and manipulation of sub-­micrometre particles

Autor
Sandra Cristina Martins Rodrigues

Instituição
UP-FCUP