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About

I’m an Applied Physics PhD with strong analytical capacity and experienced with complex and research-related problem solving. Also I was in the Industry for four years which confer me know-how in some industrial processes and research & development in an industrial context, and also in a technological centre that improve my skills on project management and application for funding. After finishing my post-graduate studies, I’ve enroll a company related with automotive industry, as process engineering and afterwards as head of quality laboratory, under the supervision of the Quality director, managing a team of six people. My post-graduate studies are an added value for a fast knowledge acquisition and adaptability and flexibility face to new issues and challenges.
After my experience in industry I was awarded with a Marie Curie CoFund Fellowship at International Iberian Nanotechnology Laboratory – INL. As a fellow I have a specific scientific project assigned although, my function at INL and also as a former researcher of INESC TEC, is getting funds through project applications (national and European project). Due to that function, I have also develop a close connection with industry aiming technology transfer. I'm presently at INESC TEC as science manager and project manager of european and national projects.
I have 47 papers in international peer-reviewed scientific journals and peer-reviewed conference proceedings and one patent (EP 3096131 A1), more than 350 citations, with an h-index 13,according to scopus. As an expert in the field, I'm invited regularly as independent expert to project evaluations, PhD thesis and peer-review in several important journals and conferences highly considered in the field of optical fiber sensors and plasmonics.

Interest
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Details

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Publications

2017

Monitoring of oxidation phases of copper thin films using long period fiber gratings

Authors
Coelho, L; Agostinho Moreira, JA; Tavares, PB; Santos, JL; Viegas, D; de Almeida, JMMM;

Publication
SENSORS AND ACTUATORS A-PHYSICAL

Abstract
Long period fiber gratings (LPFGs) were used to monitor the characteristics of copper (Cu) thin films when annealed in air atmosphere up to similar to 680 degrees C. The wavelength and the optical power shift of the resonant bands of the LPFGs when coated with the Cu thin films, were measured as a function of the annealing temperature, and were found to exhibit a different evolution comparing to a bare LPFGs. Thin films of Cu deposited on quartz (SiO2) substrates were annealed and analyzed by XRD, SEM/EDS and Raman spectroscopy, allowing to identify the formation of two distinct oxide phases at different temperatures, cuprous (Cu2O-cuprite) and cupric (CuO-tenorite) oxides, respectively. The observed features of the resonant bands of the LPFGs were found to be associated with the Cu oxide phase transitions, indicating the possibility of using LPFGs to monitor, in real time, the oxidation states of Cu thin films by following specific characteristics of the attenuation bands. In addition, LPFGs over coated with the two distinct oxidation phases of Cu were characterized for refractive index sensing in the range between 1.300 to 1.600, leading to the conclusion that the sensitivity to the refractive index of the surrounding medium of Cu coated LPFGs sensing systems can be temperature tuned.

2017

Phase-interrogated SPR sensing structures based on tapered and tip optrode optical fiber configurations with bimetallic layers

Authors
Moayyed, H; Leite, IT; Coelho, L; Santos, JL; Viegas, D;

Publication
MEASUREMENT SCIENCE AND TECHNOLOGY

Abstract
This work reports the theoretical investigation of optical fiber surface plasmon resonance sensors incorporating bimetallic layer combinations. Different metals like silver, gold, copper, and aluminum are considered to investigate the refractometric sensing properties of tapered and tip optrode phase-interrogated optical fiber plasmonic sensor structures. It is shown that the gold-silver combination, coupled to a tip optrode layout, is capable of maximizing the resolution and operation range of these sensing structures for environmental refractive index measurement.

2017

Adapting bobbert-vlieger model to spectroscopic ellipsometry of gold nanoparticles with bio-organic shells

Authors
Viegas, D; Fernandes, E; Queirós, R; Petrovykh, DY; De Beule, P;

Publication
Biomedical Optics Express

Abstract
We investigate spectroscopic imaging ellipsometry for monitoring biomolecules at surfaces of nanoparticles. For the modeling of polarimetric light scattering off surface-adsorbed core-shell nanoparticles, we employ an extension of the exact solution for the scattering by particles near a substrate presented by Bobbert and Vlieger, which offers insight beyond that of the Maxwell-Garnett effective medium approximation. Varying thickness and refractive index of a model bio-organic shell results in systematic and characteristic changes in spectroscopic parameters ? and ?. The salient features and trends in modeled spectra are in qualitative agreement with experimental data for antibody immobilization and fibronectin biorecognition at surfaces of gold nanoparticles on a silicon substrate, but achieving a full quantitative agreement will require including additional effects, such as nanoparticle-substrate interactions, into the model. © 2017 Optical Society of America.

2016

Aptamer-based fiber sensor for thrombin detection

Authors
Coelho, L; Marques Martins de Almeida, JMM; Santos, JL; da Silva Jorge, PAD; Martins, MCL; Viegas, D; Queiros, RB;

Publication
JOURNAL OF BIOMEDICAL OPTICS

Abstract
The detection of thrombin based on aptamer binding is studied using two different optical fiber-based configurations: long period gratings coated with a thin layer of titanium dioxide and surface plasmon resonance devices in optical fibers coated with a multilayer of gold and titanium dioxide. These structures are functionalized and the performance to detect thrombin in the range 10 to 100 nM is compared in transmission mode. The sensitivity to the surrounding refractive index (RI) of the plasmonic device is higher than 3100 nmRIU(-1) in the RI range 1.335 to 1.355, a factor of 20 greater than the sensitivity of the coated grating. The detection of 10 nM of thrombin was accomplished with a wavelength shift of 3.5 nm and a resolution of 0.54 nM. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

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.