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Publicações

Publicações por CAP

2015

Modal Filtering for Optimized Surface Plasmon Resonance Sensing in Multimode Plastic Optical Fibers

Autores
Cennamo, N; Coelho, L; Santos, DF; Baptista, JM; Guerreiro, A; Jorge, PAS; Zeni, LG;

Publicação
IEEE SENSORS JOURNAL

Abstract
In this paper, we present the numerical and the experimental results of a new low cost surface plasmon resonance sensor configuration. It is based on a plasmonic sensor platform and an efficient higher order modes filtering in plastic multimode fibers, exploiting a tapered plastic optical fiber at the output of the sensor system. The experimental results have demonstrated that the tapered filter positioned after the sensor system improves the performances in terms of refractive index range and depth of the resonance curve. The results are in agreement with the numerical simulations.

2015

New Trends on Optical Fiber Tweezers

Autores
Rodrigues Ribeiro, RSR; Soppera, O; Oliva, AG; Guerreiro, A; Jorge, PAS;

Publicação
JOURNAL OF LIGHTWAVE TECHNOLOGY

Abstract
In the last few decades, optical trapping has played an unique role concerning contactless trapping and manipulation of biological specimens. More recently, optical fiber tweezers (OFTs) are emerging as a desirable alternative to bulk optical systems. In this paper, an overview of the state of the art of OFTs is presented, focusing on the main fabrication methods, their features and main achievements. In addition, new OFTs fabricated by guided wave photo polymerization are reported. Their theoretical and experimental characterization is given and results demonstrating its application in the manipulation of yeast cells and the organelles of plant cells are presented.

2015

Optical Fiber Tweezers Fabricated by Guided Wave Photo-Polymerization

Autores
Ribeiro, RSR; Queiros, R; Soppera, O; Guerreiro, A; Jorge, PAS;

Publicação
PHOTONICS

Abstract
In this work the use of guided wave photo-polymerization for the fabrication of novel polymeric micro tips for optical trapping is demonstrated. It is shown that the selective excitation of linear polarized modes, during the fabrication process, has a direct impact on the shape of the resulting micro structures. Tips are fabricated with modes LP02 and LP21 and their shapes and output intensity distribution are compared. The application of the micro structures as optical tweezers is demonstrated with the manipulation of yeast cells.

2015

Passive interferometric interrogation of a magnetic field sensor using an erbium doped fiber optic laser with magnetostrictive transducer

Autores
Nascimento, IM; Baptista, JM; Jorge, PAS; Cruz, JL; Andres, MV;

Publicação
SENSORS AND ACTUATORS A-PHYSICAL

Abstract
An erbium doped (Er3+) fiber optic laser is proposed for magnetic field measurement. A pair of FBGs glued onto a magnetostrictive material (Terfenol-D rod) modulates the laser wavelength operation when subject to a static or a time dependent magnetic field. A passive interferometer is employed to measure the laser wavelength changes due to the applied magnetic field. A data acquisition hardware and a Lab VIEW software measure three phase-shifted signals at the output coupler of the interferometer and process them using two distinct demodulation algorithms. Results show that sensitivity to varying magnetic fields can be tuned by introducing a biasing magnetic field. A maximum error of 0.79% was found, for magnetic fields higher than 2.26 mT(RMS).

2015

Polymeric Optical Fiber Tweezers as a tool for single cell micro manipulation and sensing

Autores
Rodrigues Ribeiro, RSR; Soppera, O; Guerreiro, A; Jorge, PAS;

Publicação
24TH INTERNATIONAL CONFERENCE ON OPTICAL FIBRE SENSORS

Abstract
In this paper a new type of polymeric fiber optic tweezers for single cell manipulation is reported. The optical trapping of a yeast cell using a polymeric micro lens fabricated by guided photo polymerization at the fiber tip is demonstrated. The 2D trapping of the yeast cells is analyzed and maximum optical forces on the pN range are calculated. The experimental results are supported by computational simulations using a FDTD method. Moreover, new insights on the potential for simultaneous sensing and optical trapping, are presented.

2015

The efficiency of fiber optical tweezers for cell manipulation using distinct fabrication methods

Autores
Ribeiro, RSR; Soppera, O; Viegas, J; Guerreiro, A; Jorge, PAS;

Publicação
COMPLEX LIGHT AND OPTICAL FORCES IX

Abstract
In this work, the trapping efficiency of new fiber optical tweezers structures fabricated using photo polymerization and focused ion beam milling techniques is evaluated. The first fabrication methods may present limited capabilities on the tailoring of the structures, and therefore limited operation features. On the other hand, with focused ion beam milling a vast myriad of structures may be accurately fabricated, and contrarily to conventional fabrication methods, more specialized manipulation tools can be developed. In this regard, the performance of FOT for the trapping of yeast cells using spherical lenses (photo polymerization) and spiral phase lenses (FIB) will be presented. In addition, finite difference time domain (FDTD) simulations of the full vectorial optical propagation through the designed structures and the corresponding calculation of the optical forces are presented and different designs are evaluated.

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