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About

About

Susana Novais is graduated in Biomedical Engineering from the Bragança Polytechnic Institute, Portugal. In 2019 she received the Ph.D. degree in Physical Engineering at the University of Aveiro, Portugal, on optical fiber sensors for challenging media. In last 5 years, she has published about 21 papers in international journal, book chapters and conference proceedings. Her field expertise is optical fiber sensors applied to the lithium ion batteries, optical fiber designs and their applications in chemically challenging media. She is currently an Assistant Researcher at the Center for Applied Photonics (CAP) at INESC TEC and her current research interests are optical fiber sensors for medical applications.

Interest
Topics
Details

Details

  • Name

    Susana Novais
  • Role

    Assistant Researcher
  • Since

    01st April 2019
  • Nationality

    Portugal
  • Centre

    Applied Photonics
  • Contacts

    +351220402301
    susana.novais@inesctec.pt
003
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.

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

Erbium-doped fiber ring cavity for the measurement of refractive index variations

Authors
Perez Herrera, RA; Soares, L; Novais, S; Frazão, O; Silva, S;

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract

2023

Measurement of paracetamol concentration using a fiber laser system

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

Publication
2023 IEEE 7TH PORTUGUESE MEETING ON BIOENGINEERING, ENBENG

Abstract
A linear fiber laser system for measurements of paracetamol concentration is experimentally demonstrated. The cavity is based on a fiber loop mirror and an FBG centered at 1567.8 nm. The sensing head corresponds to a refractometric sensor, whose which principle of operation is based on Fresnel reflection in the fiber tip (FBG side). The system works at detected variations of paracetamol concentrations with a sensitivity of [(8.74 +/- 0.34) x10(-5)] mu W/(g/kg) and a resolution of 2.77 g/kg. The results prove that the fiber laser system could be an asset for processing industries, specifically for non-invasive and real-time measurements of concentration.