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About

About

Susana Silva is graduated in Applied Physics from the University of Porto, Portugal. She received the Ph.D. degree in Physics at the University of Porto, Portugal, on optical fiber sensors for refractive index and gas sensing. She is currently an R&D Researcher at the Center for Applied Photonics at INESC TEC. In the last few years, S. Silva has published more than 50 papers in international journals. S. Silva received the prize for best PhD Theses in Optics and Photonics of 2013. Her field of expertise is the fabrication of optical fiber sensors for monitoring of physical parameters. Her current research interests are optical sensors for biomedical applications and distributed fiber optic sensing for biodiversity applications.

Interest
Topics
Details

Details

  • Name

    Susana Oliveira Silva
  • Role

    Assistant Researcher
  • Since

    01st March 2005
  • Nationality

    Portugal
  • Centre

    Applied Photonics
  • Contacts

    +351220402301
    susana.o.silva@inesctec.pt
006
Publications

2024

Linear Fiber Laser Configurations for Optical Concentration Sensing in Liquid Solutions

Authors
Soares, L; Perez-Herrera, RA; Novais, S; Ferreira, A; Silva, S; Frazao, O;

Publication
PHOTONICS

Abstract
In this study, different configurations based on linear fiber lasers were proposed and experimentally demonstrated to measure the concentration of liquid solutions. Samples of paracetamol liquid solutions with different concentrations, in the range from 52.61 to 201.33 g/kg, were used as a case-study. The optical gain was provided by a commercial bidirectional Erbium-Doped Fiber Amplifier (EDFA) and the linear cavity was obtained using two commercial Fiber Bragg Gratings (FBGs). The main difference of each configuration was the coupling ratio of the optical coupler used to extract the system signal. The sensing head corresponded to a Single-Mode Fiber (SMF) tip that worked as an intensity sensor. The results reveal that, despite the optical coupler used (50:50, 60:40, 70:30 or 80:20), all the configurations reached the laser condition, however, the concentration sensing was only possible using a laser drive current near to the threshold value. The configurations using a 70:30 and an 80:20 optical coupler allowed paracetamol concentration measurements with a higher sensitivity of (-3.00 +/- 0.24) pW/(g/kg) to be performed. In terms of resolution, the highest value obtained was 1.75 g/kg, when it was extracted at 20% of the output power to the linear cavity fiber laser configuration.

2024

Enhanced Sensitivity in Optical Sensors through Self-Image Theory and Graphene Oxide Coating

Authors
Cunha, C; Monteiro, C; Vaz, A; Silva, S; Frazao, O; Novais, S;

Publication
SENSORS

Abstract
This paper presents an approach to enhancing sensitivity in optical sensors by integrating self-image theory and graphene oxide coating. The sensor is specifically engineered to quantitatively assess glucose concentrations in aqueous solutions that simulate the spectrum of glucose levels typically encountered in human saliva. Prior to sensor fabrication, the theoretical self-image points were rigorously validated using Multiphysics COMSOL 6.0 software. Subsequently, the sensor was fabricated to a length corresponding to the second self-image point (29.12 mm) and coated with an 80 mu m/mL graphene oxide film using the Layer-by-Layer technique. The sensor characterization in refractive index demonstrated a wavelength sensitivity of 200 +/- 6 nm/RIU. Comparative evaluations of uncoated and graphene oxide-coated sensors applied to measure glucose in solutions ranging from 25 to 200 mg/dL showed an eightfold sensitivity improvement with one bilayer of Polyethyleneimine/graphene. The final graphene oxide-based sensor exhibited a sensitivity of 10.403 +/- 0.004 pm/(mg/dL) and demonstrated stability with a low standard deviation of 0.46 pm/min and a maximum theoretical resolution of 1.90 mg/dL.

2024

Coreless Silica Fiber Sensor based on Self-Image Theory and coated with Graphene Oxide

Authors
Cunha, C; Monteiro, C; Vaz, A; Silva, S; Frazao, O; Novais, S;

Publication
OPTICAL SENSING AND DETECTION VIII

Abstract
This work provides a method that combines graphene oxide coating and self-image theory to improve the sensitivity of optical sensors. The sensor is designed specifically to measure the amount of glucose present quantitatively in aqueous solutions that replicate the range of glucose concentrations found in human saliva. COMSOL Multiphysics 6.0 was used to simulate the self-imaging phenomenon using a coreless silica fiber (CSF). For high-quality self-imaging, the second and fourth self-imaging points are usually preferred because of their higher coupling efficiency, which increases the sensor sensitivity. However, managing the fourth self-image is more difficult because it calls for a longer CSF length. As a result, the first and second self-image points were the focus of the simulation in this work. After the simulation, using the Layerby-Layer method, the sensor was constructed to a length that matched the second self-image point (29.12 mm) and coated with an 80 mu m/mL graphene oxide layer. When comparing uncoated and graphene oxide-covered sensors to measure glucose in liquids ranging from 25 to 200 mg/dL, one bilayer of polyethyleneimine/graphene demonstrated an eight-fold improvement in sensitivity. The final sensor, built on graphene oxide, showed stability with a low standard deviation of 0.6 pm/min. It also showed sensitivity at 10.403 +/- 0.004 pm/(mg/dL) with a limit of detection of 9.15 mg/dL.

2023

Measurement of Paracetamol Concentration Using an Erbium-Doped Fiber Ring Cavity

Authors
Soares, L; Perez Herrera, RA; Novais, S; Ferreira, A; Silva, S; Frazao, O;

Publication
PHOTONICS

Abstract
Process Analytical Technology (PAT) has been increasingly used in the pharmaceutical industry to monitor essential parameters in real-time during pharmaceutical processes. The concentration of Active Pharmaceutical Ingredients (APIs), such as paracetamol, is one of these parameters, and controlling its variations allows for optimization of the production process. In this study, a refractometric sensor, implemented by an interrogation system based on an Erbium-Doped Fiber Ring Cavity (EDFRC), was presented and experimentally demonstrated. The Cavity Ring proposed included a 1 x 3 coupler. One port of the coupler was used to increase the optical power of the system through a Fiber Bragg Grating (FBG), and the other two ports were used as sensing head and reference. The sensor detected variations of paracetamol concentration with a sensitivity of [(-1.00 +/- 0.05) x 10(-3)] nW/(g/kg) and a resolution of 5.53 g/kg. The results demonstrate the potential of this technology as a possible non-invasive PAT tool.

2023

Fiber Loop Mirror Based on Optical Fiber Circulator for Sensing Applications

Authors
Robalinho, P; Soares, B; Lobo, A; Silva, S; Frazao, O;

Publication
SENSORS

Abstract
In this paper, a different Fiber Loop Mirror (FLM) configuration with two circulators is presented. This configuration is demonstrated and characterized for sensing applications. This new design concept was used for strain and torsion discrimination. For strain measurement, the interference fringe displacement has a sensitivity of (0.576 +/- 0.009) pm.mu epsilon(-1). When the FFT (Fast Fourier Transformer) is calculated and the frequency shift and signal amplitude are monitored, the sensitivities are (-2.1 +/- 0.3) x 10(-4) nm(-1) mu epsilon(-1) and (4.9 +/- 0.3) x 10(-7) mu epsilon(-1), respectively. For the characterization in torsion, an FFT peaks variation of (-2.177 +/- 0.002) x 10(-12) nm(-1)/degrees and an amplitude variation of (1.02 +/- 0.06) x 10(-3)/degrees are achieved. This configuration allows the use of a wide range of fiber lengths and with different refractive indices for controlling the free spectral range (FSR) and achieving refractive index differences, i.e., birefringence, higher than 10(-2), which is essential for the development of high sensitivity physical parameter sensors, such as operating on the Vernier effect. Furthermore, this FLM configuration allows the system to be balanced, which is not possible with traditional FLMs.

Supervised
thesis

2022

Manipulation of polarization through optical devices coated with azobenzenes for applications in communications and sensors

Author
Beatriz Gomes Soares

Institution
INESCTEC

2022

Estudo e desenvolvimento de novas configurações de sensores em fibra ótica para monitorização de cristalizadores na área farmacêutica

Author
Liliana Patrícia Santos Soares

Institution
INESCTEC

2020

Raman Endoscopy Using Optical Fiber Technology

Author
João Pedro Marques

Institution
INESCTEC

2020

Estudo e desenvolvimento de novas configurações de sensores em fibra ótica para monitorização de cristalizadores na área farmacêutica

Author
Liliana Patrícia Santos Soares

Institution
INESCTEC

2020

Desenvolvimento de sensores óticos para aplicações biomiméticas

Author
António José Meireles Martins

Institution
INESCTEC