Publications

Publications by José Luís Santos

1998

<title>Extended-range interrogation scheme for fibre Bragg grating sensors using a multimode laser diode</title>

Authors
Moreira, PJ; Ferreira, LAA; Santos, JL; Farahi, F;

Publication
European Workshop on Optical Fibre Sensors

Abstract

1998

<title>Simultaneous strain and temperature sensing using an interferometrically interrogated fibre Bragg grating written in bowtie fibre</title>

Authors
Ferreira, LAA; Araujo, FM; Santos, JL; Farahi, F;

Publication
European Workshop on Optical Fibre Sensors

Abstract

1999

<title>Active WDM demodulation scheme for fiber Bragg grating sensors</title>

Authors
Araujo, FM; Ferreira, LAA; Santos, JL; Farahi, F;

Publication
Fiber Optic and Laser Sensors and Applications; Including Distributed and Multiplexed Fiber Optic Sensors VII

Abstract

2004

<title>High-resolution absolute-distance measurements using multiple-tunable fiber Bragg gratings</title>

Authors
Luquin, E; Frazao, O; Ferreira, LA; Araujo, FM; Lopez-Amo, M; Santos, JL;

Publication
Second European Workshop on Optical Fibre Sensors

Abstract

2005

Self-referenced intensity based optical fiber temperature probes for luminescent chemical sensors using quantum dots

Authors
Jorge, PAS; Mayeh, M; Benrashid, R; Caldas, P; Santos, JL; Farahi, F;

Publication
17th International Conference on Optical Fibre Sensors, Pts 1 and 2

Abstract
The use of semiconductor nano-particles as temperature probes in luminescence chemical sensing applications is addressed. Temperature changes the intensity, the peak wavelength and the spectral width of the quantum dots luminescent emission in a linear and reversible way. Results are presented that show the feasibility of implementing a self-referenced intensity based sensor to perform temperature measurements independent of the optical power level in the sensing system. Additionally, it is demonstrated that self-referenced temperature measurements in multiple points could be performed using reflection or transmission based optical fiber configurations.

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2005

Intensity based luminescent optical fiber oxygen sensor using quantum dots

Authors
Jorge, PAS; Mayeh, M; Benrashid, R; Caldas, P; Santos, JL; Farahi, F;

Publication
17th International Conference on Optical Fibre Sensors, Pts 1 and 2

Abstract
The suitability of semiconductor nanoparticles to provide a reference signal in luminescence based chemical sensors is addressed. A CdSe-ZnS nanocrystal, with emission peak at 520 nm is used to provide a reference signal. Measurements of oxygen concentration, which are based on the dynamic quenching of the luminescence of a Ruthenium complex, are performed. Both dye and the nanocrystal are immobilized in a sol-gel matrix and are excited by a blue LED. Results are presented showing that the ratio between the reference and the sensor signals is highly insensitive to fluctuations of the excitation optical power. Preliminary results show that nanocrystals could be used to measure temperature and provide a reference signal.

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