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About

About

Jose Manuel Marques Martins de Almeida received the
Graduate degree in applied physics (optics and electronics)
in 1987 and the Ph.D. degree in 1998 from the
University of Porto, Porto, Portugal. Since 2000, he has the
position of an Associate Professor at the Department of
Physics, Universidade de Trás os Montes e Alto Douro, Vila
Real, Portugal, and received Habilitation in 2006 from the
same University. He is currently a Senior Researcher in the
Centre for Applied Photonics of INESC TEC, Porto. His current
research interests include optical sensors, integrated
optics, spectroscopy, and biophysics.

Interest
Topics
Details

Details

Publications

2016

Characterization of zinc oxide coated optical fiber long period gratings with improved refractive index sensing properties

Authors
Coelho, L; Viegas, D; Santos, JL; de Almeida, JMMM;

Publication
SENSORS AND ACTUATORS B-CHEMICAL

Abstract
A fiber-optic refractive index (RI) sensor based on a long period fiber grating (LPFG) coated with a zinc oxide (ZnO) thin film was fabricated and characterized. A method to overcoat the LPFG's with a homogeneous ZnO thin films was developed. Characterization of ZnO thin films, deposited simultaneously on silicon (Si) planar substrates, was performed using Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy and X-ray Photoelectron Spectroscopy. The LPFGs with ZnO coatings from 29 to 145 nm of thickness were characterized and compared in terms of the wavelength shift and the intensity of the attenuation bands changing the surrounding refractive index (SRI) from 1.300 to 1.600. An average wavelength sensitivity of similar to 7162 nm/RIU was achieved in the RI range from 1.440 to 1.456 and more than 12,000 nm/RIU at 1.440 RI. Using a ZnO film thickness of 116 nm and in the RI region between 1.320 and 1.360 the average sensitivity of similar to 806 nm/RIU was measured for a 145 nm thick film. Working as an intensity sensing device, the 87 nm coated LPFG shows a linear sensitivity of 216.4 dB/RIU in a wide range of RI from 1.340 to 1.420.

2016

Fabrication and Characterization of Metal Oxide-Coated Long-Period Fiber Gratings

Authors
Coelho, L; Santos, JL; Viegas, D; Marques Martins de Almeida, JMMM;

Publication
JOURNAL OF LIGHTWAVE TECHNOLOGY

Abstract
Sensors based on long-period fiber gratings (LPFGs) over coated with metal oxide were fabricated and characterized for refractive index (RI) sensing. Oxidation of Ni, Ti, Al, and Cr was monitored in real time by following the features of the LPFG attenuation band. Themetals were deposited simultaneously on top of Si substrates for further chemical and morphological analysis. Wavelength sensitivities (nm/RIU) of about 10 437 at 1.432, 1150 at 1.400, 20 125 at 1.448, and 875 at 1.420 were achieved for LPFGs coated, with 68 nm of Ni, 60 nm of TiO2, 50 nm of Al2O3, and 62 nm of Cr2O3, respectively. For surrounding RI higher than the cladding RI, the wavelength sensitivities are 1937, 6801, 5762, and 3051 nm/RIU at 1.457 for the Ni, Ti, Al, and Cr oxides, respectively. Working as intensity sensing devices sensitivities up to 167 dB/RIU were measured. Metal oxide coated LPFGs leads to wavelength sensitivity enhancement comparing to bare LPFGs and may be used in systems with RI higher than the fiber cladding, a region where bare LPFGs are insensitive.

2016

Optical sensor based on hybrid FBG/titanium dioxide coated LPFG for monitoring organic solvents in edible oils

Authors
Coelho, L; Viegas, D; Santos, JL; Marques Martins de Almeida, JMMM;

Publication
TALANTA

Abstract
A hybrid optical sensing scheme based on a fiber Bragg grating (FBG) combined with a titanium dioxide coated long period fiber grating (LPFG) for monitoring organic solvents in high refractive index edible oils is reported. In order to investigate and optimize the sensor performance, two different FBG/LPFG interrogation systems were investigated. The readout of the sensor was implemented using either the wavelength shift of the LPFG resonance dip or the variation in the optical power level of the reflected/transmitted light at the FBG wavelength peak, which in turn depends on the wavelength position of the LPFG resonance. Hexane concentrations up to 20%V/V, corresponding to the refractive index range from 1.451 to 1.467, were considered. For the transmission mode of operation, sensitivities of 1.41 nm/%V/V and 0.11 dB/%V/V, with resolutions of 0.58%V/V and 0.29%V/V, were achieved when using the LPFG wavelength shift and the FBG transmitted optical power, respectively. For the FBG reflection mode of operation, a sensitivity of 0.07 dB/V/V and a resolution better than 0.16%V/V were estimated.

Supervised
thesis

2017

Development of optical biosensors for monitoring the deterioration of fresh meat and fish

Author
HELENA CATARINA ARAÚJO SOARES GUEDES VASCONCELOS

Institution
UTAD

2016

Aplicação de Espetroscopia de Infravermelhos na Predição daDeterioração de Carne de BovinoMaronês Tratada com Óleos Essenciais

Author
Joana Isabel Teixeira Ramiro Vilela

Institution
UTAD

2016

Estudo da adulteração de peixe freco por espectroscopia de infravermelhos

Author
Nuno Filipe campos Sousa

Institution
UTAD

2016

Estudo de adulteração de carne e peixe fresco

Author
Maria João Moreira

Institution
UTAD

2016

Effect of essential oil of Myrtus communis L. and Rosmarinus officinalis L. on growth control of Listeria monocytogenes in fresh cheese

Author
ANA CATARINA COSTA DA SILVA

Institution
UTAD