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About

About

João M. Maia received the MSc degree in Physics Engineering from the University of Porto, Portugal in 2016. He is currently a PhD Physics student in the same instituion.

In 2015 he joined the research centre INESC TEC, where he has been working on femtosecond laser micromachining and fabrication of optofluidic devices.

Interest
Topics
Details

Details

  • Nationality

    Portugal
  • Centre

    Applied Photonics
  • Contacts

    +351220402301
    joao.m.maia@inesctec.pt
001
Publications

2019

Loss Mechanisms of Optical Waveguides Inscribed in Fused Silica by Femtosecond Laser Direct Writing

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

Publication
Journal of Lightwave Technology

Abstract

2019

Advances in Fs-Laser Micromachining Towards the Development of Optofluidic Devices

Authors
Maia, JM; Amorim, VA; Alexandre, D; Marques, PVS;

Publication
Springer Series in Optical Sciences

Abstract
In this chapter the developments made in femtosecond laser micromachining for applications in the fields of optofluidics and lab-on-a-chip devices are reviewed. This technology can be applied to a wide range of materials (glasses, crystals, polymers) and relies on a non-linear absorption process that leads to a permanent alteration of the material structure. This modification can induce, for instance, a smooth variation of the refractive index or generate etching selectivity, which can be used to form integrated optical circuits and microfluidic systems, respectively. Unlike conventional techniques, fs-laser micromachining offers a way to produce high-resolution three-dimensional components and integrate them in a monolithic approach. Recent advances made in two-photon polymerization have also enabled combination of polymeric structures with microfluidic channels, which can provide additional functionalities, such as fluid transport control. In particular, here it is emphasised the integration of microfluidic systems with optical layers and polymeric structures for the fabrication of miniaturized hybrid devices for chemical synthesis and biosensing. © 2019, Springer Nature Switzerland AG.

2019

Spectral Tuning of Long Period Fiber Gratings Fabricated by Femtosecond Laser Micromachining through Thermal Annealing

Authors
Viveiros, D; Almeida, JMMMd; Coelho, L; Vasconcelos, H; Amorim, VA; Maia, JM; Jorge, PAS;

Publication
Proceedings

Abstract
A femtosecond laser direct writing system was developed to explore the fabrication of long-period fiber gratings (LPFGs) in SMF28 fibers. The LPFGs, showing the mode LP1,6 at 1500 nm, were exposed to high-temperature annealing up to 950 °C. Modifications in the refractive index (RI) modulation are observed through a blue-shift in the LPFG attenuation bands and above 850 °C, the mode LP1,7 appear at 1600 nm. The wavelength sensitivity to external RI from 1.300 to 1.452 was estimated for both modes before and after annealing. Greater sensitivity was found for the higher order mode in the entire range reaching 2400 nm/RIU around 1.440.

2019

Spectral characteristics of optical waveguides fabricated in glass by femtosecond laser direct writing

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

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
The fabrication of optical waveguides with femtosecond laser direct writing is reported in two materials, Suprasil1 and Eagle2000. The influence of typical fabrication parameters, such as pulse energy and scan velocity, on the waveguide's spectral characteristics is explored from 500 to 1700 nm. Tests conducted in Suprasil1 evidence a strong presence of Rayleigh scattering, hindering the production of low-loss waveguides at short wavelengths. On the other hand, optical waveguides fabricated in Eagle2000 exhibited lower insertion losses at short wavelengths, enabling the fabrication of low-loss broadband optical waveguides with a two order of magnitude higher scan velocity when compared with Suprasil1. © 2019 SPIE.

2019

Femtosecond laser micromachining of Fabry-Pérot interferometers in fused silica for refractive index sensing

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

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract
A Fabry-Pérot interferometer was fabricated inside a fused silica substrate through femtosecond laser micromachining. The influence of the waveguide's writing parameters on the measured signal's quality was studied for an interferometer with a 27-µm wide cavity. Optimal signal-to-noise ratio and fringe visibility were obtained for waveguides written at 75 nJ and 50 µm/s. The same device was characterized with different refractive index liquids, and a maximum sensitivity of 1181.4±23.6 nm/RIU was obtained in the index range of 1.2962 to 1.3828 (at 1550 nm) for the spectral order o?'š = 46. © 2019 SPIE.