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Publicações

Publicações por Ariel Guerreiro

2013

New theoretical and experimental methods for the design of fiber optic tweezers

Autores
Ribeiro, RSR; Guerreiro, A; Ecoffet, C; Soppera, O; Jorge, PAS;

Publicação
FIFTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS

Abstract
This paper presents a study of optical forces acting on dielectric particles in media of distinct refractive index. The radiation pressure forces produced by optical tweezers are calculated using the finite difference time domain method as well as the Lorentz force on electric dipoles. The model considers a 2-dimension structure composed of a waveguide and a dielectric microparticle. Furthermore, the paper presents preliminary experimental results concerning the implementation of fiber optical tweezers system based on polymeric lensed fibers.

2013

Numerical investigation of a refractive index SPR D-type optical fiber sensor using COMSOL multiphysics

Autores
Santos, DF; Guerreiro, A; Baptista, JM;

Publicação
Photonic Sensors

Abstract
Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance (SPR) phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized. © 2012 The Author(s).

2014

Optical sensing based in plasmonics and the metamaterials enhancement factor

Autores
Moayyed, H; Leite, IT; Coelho, L; Santos, JL; Guerreiro, A; Viegas, D;

Publicação
Latin America Optics and Photonics Conference, LAOP 2014

Abstract
The recent burst of R&D activity in Plasmonics, associated with the possibility of materials nanostructuring which enables the access to metamaterials, has been strongly impacting many branches of optics such as imaging, data recording and sensing. This talk details the factors that turned the combination Plasmonics and Metamaterials a huge opportunity to optical sensing.© OSA 2014.

2017

Optimization of modal sensitivity in nanowire SPR multimode sensor

Autores
Santos, DF; Guerreiro, A; Baptista, JM;

Publicação
2017 25TH INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS (OFS)

Abstract
This paper presents a multimode fiber sensor that uses surface plasmon resonance on a metallic wire to measure refractive index. Numerical simulations based on the finite element method reveal the sensor supports several plasmon modes in the wire capable of coupling with the multiples optical fiber modes. Therefore, the sensor configuration creates multiple resonances at different wavelengths, with different values of the loss, sensitivity, among other parameters. Choosing the appropriate mode and filtering out the rest of the modes allows to optimize the sensor performance. In the present work a sensitivity of 5340nm/RIU and resolution of 1.87x10(-6) RIU were found.

2014

Rapid fabrication of polymeric micro lenses for optical fiber trapping and beam shaping

Autores
Ribeiro, RSR; Queiros, RB; Ecoffet, C; Soppera, O; Oliva, A; Guerreiro, A; Jorge, PAS;

Publicação
OPTICAL TRAPPING AND OPTICAL MICROMANIPULATION XI

Abstract
This work reports a new type of optical fiber tweezers based on polymeric micro-lenses. The lenses are achieved by means of an economical and fast fabrication process, using an in-fiber photo-polymerization technique. The polymerization radiation is guided towards the fiber tip creating a polymeric waveguide. The method allows tailoring the geometry of the tip by adjusting the fabrication parameters. Furthermore, more complex shapes can be fabricated by exploring modal effects at the polymerization/trapping wavelengths, which can be used for different applications such as trapping, beam shaping and patterned illumination.

2013

Remote fiber sensors and optical amplification

Autores
Pontes, MJ; Coelho, TVN; Carvalho, JP; Santos, JL; Guerreiro, A;

Publicação
8TH IBEROAMERICAN OPTICS MEETING AND 11TH LATIN AMERICAN MEETING ON OPTICS, LASERS, AND APPLICATIONS

Abstract
This work discusses remote fiber sensors enabled by optical amplification. Continuous wave numerical modeling based on the propagation of pumps and signal lasers coupled to optical fibers explores Raman amplification schemes to predict the sensor's behavior. Experimental analyses report the results to a temperature remote optical sensor with 50 km distance between the central unit and the sensor head. An electrical interrogation scheme is used due to their low cost and good time response. Different architectures in remote sensor systems are evaluated, where diffraction gratings are the sensor element. A validation of calculated results is performed by experimental analyses and, as an application, the noise generated by Raman amplification in the remote sensors systems is simulated applying such numerical modeling. The analyses of sensors systems based on diffraction gratings requires optical broadband sources to interrogate the optical sensor unit, mainly in long period gratings that shows a characteristic rejection band. Therefore, the sensor distance is limited to a few kilometers due to the attenuation in optical fibers. Additional attenuation is introduced by the sensor element. Hence, to extend the distance in the optical sensor system, the optical amplification system is needed to compensate the losses in the optical fibers. The Raman amplification technology was selected mainly due to the flexibility in the gain bandwidth. The modeling can be applied to sensor systems that monitor sites located at long distances, or in places that the access is restricted due to harsh environment conditions in such cases conventional sensors are relatively fast deteriorated.

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