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Tópicos
de interesse
Detalhes

Detalhes

007
Publicações

2022

Tunable Plasmonic Resonance Sensor Using a Metamaterial Film in a D-Shaped Photonic Crystal Fiber for Refractive Index Measurements

Autores
Cardoso, MP; Silva, AO; Romeiro, AF; Giraldi, MTR; Costa, JCWA; Santos, JL; Baptista, JM; Guerreiro, A;

Publicação
APPLIED SCIENCES-BASEL

Abstract
Subwavelength cells of metallic nanorods arrayed in a dielectric background, termed “metamaterials”, present bulk properties that are useful to control and manipulate surface plasmon resonances. Such feature finds tremendous potential in providing a broad manifold of applications for plasmonic optical sensors. In this paper, we propose a surface-plasmon-resonance-based sensor with spectral response tunable by the volume fraction of silver present in a metamaterial layer deposited on a D-shaped photonic crystal fiber. Using computational simulations, we show that sensitivity and resolution can be hugely altered by changing the amount of constituents in the metamaterial, with no further modifications in the structure of the sensor. Moreover, the designed sensor can also be applied to label the average volume fraction of silver in the metamaterial layer and then to estimate its effective constitutive parameters.

2022

A Simple Optical Sensor Based on Multimodal Interference Superimposed on Additive Manufacturing for Diameter Measurement

Autores
Cardoso, VHR; Caldas, P; Giraldi, MTR; Fernandes, CS; Frazao, O; Costa, JCWA; Santos, JL;

Publicação
SENSORS

Abstract
In many areas, the analysis of a cylindrical structure is necessary, and a form to analyze it is by evaluating the diameter changes. Some areas can be cited: pipelines for oil or gas distribution and radial growth of trees whose diameter changes are directly related to irrigation and the radial expansion since it depends on the water soil deficit. For some species, these radial variations can change in around 5 mm. This paper proposes and experimentally investigates a sensor based on a core diameter mismatch technique for diameter changes measurement. The sensor structure is a combination of a cylindrical piece developed using a 3D printer and a Mach–Zehnder interferometer. The pieces were developed to assist in monitoring the diameter variation. It is formed by splicing an uncoated short section of MMF (Multimode Fiber) between two standard SMFs (Singlemode Fibers) called SMF-MMF-SMF (SMS), where the MMF length is 15 mm. The work is divided into two main parts. Firstly, the sensor was fixed at two points on the first developed piece, and the diameter reduction caused dips or peaks shift of the transmittance spectrum due to curvature and strain influence. The fixation point (FP) distances used are: 5 mm, 10 mm, and 15 mm. Finally, the setup with the best sensitivity was chosen, from first results, to develop another test with an optimization. This optimization is performed in the printed piece where two supports are created so that only the strain influences the sensor. The results showed good sensitivity, reasonable dynamic range, and easy setup reproduction. Therefore, the sensor could be used for diameter variation measurement for proposed applications.

2021

Experimental investigation of a strain gauge sensor based on Fiber Bragg Grating for diameter measurement

Autores
Cardoso, VHR; Caldas, P; Giraldi, MTR; Frazao, O; de Carvalho, CJR; Costa, JCWA; Santos, JL;

Publicação
OPTICAL FIBER TECHNOLOGY

Abstract
A strain gauge sensor based on Fiber Bragg Grating (FBG) for diameter measurement is proposed and experimentally demonstrated. The sensor is easily fabricated inserting the FBG on the strain gauge—it was fabricated using a 3D printer—and fixing the FBG in two points of this structure. The idea is to vary the diameter of the structure. We developed two experimental setups, the first one is used to evaluate the response of the FBG to strain and the second one to assess the possibility of using the structure developed to monitor the desired parameter. The results demonstrated that the structure can be used as a way to monitor the diameter variation in some applications. The sensor presented a sensitivity of 0.5361 nm/mm and a good linear response of 0.9976 using the Strain Gauge with FBG and fused taper. © 2020 Elsevier Inc.

2021

Optical Sensors for Industry 4.0

Autores
Santos, JL;

Publicação
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS

Abstract
This work addresses the role of optical sensing within the new emerging paradigm Industry 4.0. It starts with some thoughts about complex systems and their inherent need of enlarged sensorial tools. Then, the principles of optical sensing are presented with identification of the two principal types. After summarizing what is meant by Industry 4.0, it is detailed how optical sensing can contribute to the raise up of this new industrial concept, focusing on vision, physical sensing, chemical sensing, and sensor multiplexing. Emphasis is given in fiber optic sensing and, when feasible, in fiber Bragg grating sensing technology. Finally, some final remarks are delivered.

2021

Second-Order Dispersion Sensor Based on Multi-Plasmonic Surface Resonances in D-Shaped Photonic Crystal Fibers

Autores
Cardoso, MP; Silva, AO; Romeiro, AF; Giraldi, MTR; Costa, JCWA; Santos, JL; Baptista, JM; Guerreiro, A;

Publicação
PHOTONICS

Abstract
This paper proposes a scheme to determine the optical dispersion properties of a medium using multiple localized surface plasmon resonances (SPR) in a D-shaped photonic crystal fiber (PCF) whose flat surface is covered by three adjacent gold layers of different thicknesses. Using computational simulations, we show how to customize plasmon resonances at different wavelengths, thus allowing for obtaining the second-order dispersion. The central aspect of this sensing configuration is to balance miniaturization with low coupling between the different localized plasmon modes in adjacent metallic nanostructures. The determination of the optical dispersion over a large spectral range provides information on the concentration of different constituents of a medium, which is of paramount importance when monitoring media with time-varying concentrations, such as fluidic media.

Teses
supervisionadas

2016

Research and development of optical fibre sensors based on thin film coating technology

Autor
Luís Carlos Costa Coelho

Instituição
UP-FCUP

2016

Analysis of Plasmonics Based Fiber Optic Sensing Structures

Autor
Hamed Moayyed

Instituição
UP-FCUP

2015

Fiber Sensing Based on New Structures and Post-Processing Enhancement

Autor
Marta Sofia dos Anjos Ferreira

Instituição
UP-FEP