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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

  • Nome

    Paulo Vicente Marques
  • Cargo

    Coordenador de Centro
  • Desde

    01 julho 2000
011
Publicações

2024

Study on fs-laser machining of optical waveguides and cavities in ULE® glass

Autores
Maia, JM; Marques, PVS;

Publicação
JOURNAL OF OPTICS

Abstract
The potential of ultrafast laser machining for the design of integrated optical devices in ULE (R) glass, a material known for its low coefficient of thermal expansion (CTE), is addressed. This was done through laser direct writing and characterization of optical waveguides and through the fabrication of 3D cavities inside the glass by following laser irradiation with chemical etching. Type I optical waveguides were produced and their internal loss mechanisms at 1550 nm were studied. Coupling losses lower than 0.2 dB cm-1 were obtained within a wide processing window. However, propagation loss lower than 4.2-4.3 dB cm-1 could not be realized, unlike in other glasses, due to laser-induced photodarkening. Selective-induced etching was observed over a large processing window and found to be maximum when irradiating the glass with a fs-laser beam linearly polarised orthogonally to the scanning direction, akin to what is observed in fused silica laser-machined microfluidic channels. In fact, the etching selectivity and surface roughness of laser-machined ULE (R) glass was found to be similar to that of fused silica, allowing some of the already reported microfluidic and optofluidic devices to be replicated in this low CTE glass. An example of a 3D cavity with planar-spherically convex interfaces is given. Due to the thermal properties of ULE (R) glass, these cavities can be employed as interferometers for wavelength and/or temperature referencing.

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 mu m 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

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
The potential of evanescent Mach-Zehnder interferometers, embedded in Eagle2000 substrates, as refractive index sensors was assessed. For that, femtosecond laser direct writing and wet etching were used to fabricate and expose the sensing arm at the surface of the glass substrate, while keeping the reference arm buried. From the analysis of the structures' spectral response, we found that the wavelength shift of the different order peaks increased greatly for refractive indices nearing that of the glass, indicating a greater overlap between the guided mode's evanescent field and the external medium. Therefore, a maximum sensitivity of 10271 nm/RIU was obtained at a refractive index of 1.491. The sensitivity in the refractive index range of water-based solutions was, on the other hand, limited to 446 +/- 39 nm/RIU. Due to the geometry of the device, applications with films deposited at the surface of the substrate and PDMS based microfluidic channels can be explored.

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.

Teses
supervisionadas

2022

Fabrication of opticals Ensing devices by 3D laser  micromachining

Autor
Carlos Duarte Rodrigues Viveiros

Instituição
UP-FCUP

2021

Glass welding using femtosecond lasers and applications in optofluidics

Autor
António Francisco Neves Silva Antão Ferreira

Instituição
UP-FCUP

2021

Fabrication of opticals Ensing devices by 3D laser  micromachining

Autor
Carlos Duarte Rodrigues Viveiros

Instituição
UP-FCUP

2021

Fabrication of Optofluidic Systems by Femtosecond Laser Micromachining

Autor
João Miguel Mendes da Silva Maia

Instituição
UP-FCUP

2021

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

Autor
Vítor Alexandre Oliveira Amorim

Instituição
UP-FCUP