Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by Susana Novais

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.

2023

Transmissive glucose concentration plasmonic Au sensor based on unclad optical fiber

Authors
Cunha, C; Assuncao, AS; Monteiro, CS; Leitao, C; Mendes, JP; Silva, S; Frazao, O; Novais, S;

Publication
2023 IEEE 7TH PORTUGUESE MEETING ON BIOENGINEERING, ENBENG

Abstract
Using surface resonance (SPR) as a sensitivity enhancer, this work describes the development of a transmissive multimode optical fiber sensor with a gold (Au) thin film that measures glucose concentration. The fiber's cladding was initially removed, and an Au layer was then sputtered onto its surface to simultaneously excite SPR and reflect light, making the SPR sensor extremely sensitive to changes in the environment's refractive index. A range of glucose concentrations, from 0.0001 to 0.5000 g/ml, were tested on the sensor. A maximum sensitivity of 161.302 nm/(g/mL) was attained for the lowest glucose concentration, while the highest concentration yielded a sensitivity of 312.000 nm/(g/mL). The proposed sensor's compact size, high sensitivity, good stability and practicality make it a promising candidate for a range of applications, including detecting diabetes.

2023

Paracetamol concentration-sensing scheme based on a linear cavity fiber laser configuration

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

Publication
OPTICAL FIBER TECHNOLOGY

Abstract
A paracetamol concentration-sensing scheme based on a linear cavity fiber laser configuration is demonstrated experimentally. The laser cavity has a fiber sensor at one end, that allows refractive index measurements. The refractometer consists of a cleaved fiber tip combined with an FBG functioning as a reflecting mirror. The combination of a fiber loop mirror at the other end allows to reflect all the light from the FBG and refractometer, forming a linear cavity. By measuring the intensity variation of the Fresnel reflection at the fiber-to-liquid interface, the measured concentration is linear and have a concentration sensitivity of [( - 8.74 & PLUSMN; 0.34) x 10-5 ] & mu;W/(g/kg), over a range of 52.61 to 219.25 g/kg, and with a resolution of 2.77 g/kg. The results obtained present high stability and prove the potential of the fiber laser system to performed realtime measurements of concentration, in a non-invasive way.

2018

Relative Humidity Fiber Sensor Based on Multimode Interferometer Coated with Agarose-Gel

Authors
Novais, S; Ferreira, MS; Pinto, JL;

Publication
COATINGS

Abstract
In this work, a relative humidity (RH) sensor based on a structure with multimode interference is proposed and experimentally demonstrated. The multimode sensor is fabricated by fusion splicing a coreless fiber section to a single mode fiber. A hydrophilic agarose gel is coated on the coreless fiber, using the dip coating technique. By changing the surrounding RH, the refractive index of the coated agarose gel will change, causing a wavelength shift of the peak in the reflection spectra. For RH variations in the range between 60.0%RH and 98.5%RH, the sensor presents a maximum sensitivity of 44.2 pm/%RH, and taking in consideration the interrogation system, a resolution of 0.5%RH is acquired. This sensor has a great potential in real time RH monitoring and can be of interest for applications where a control of high levels of relative humidity is required.

2018

Glucose measurements with optical fiber sensor based on coreless silica fiber

Authors
Novais, S; Ferreira, CIA; Ferreira, MS; Pinto, JL;

Publication
Optics InfoBase Conference Papers

Abstract
A reflective fiber optic sensor based on multimode interference for the measurement of glucose aqueous solutions is proposed. A maximum experimental resolution of 0.04 wt.% of glucose is achieved. © OSA 2018 © 2018 The Author(s)

2018

Optical fiber tip sensor for determining the thermo-optic coefficient of ethanol-water mixtures

Authors
Ferreira, MS; Novais, S; Pinto, JL;

Publication
Optics InfoBase Conference Papers

Abstract
A multimode interferometer based on an etched coreless optical fiber tip is proposed for the determination of the thermo-optic coefficient of ethanol-water mixtures, through refractive index and temperature measurements. © OSA 2018 © 2018 The Author(s)

  • 4
  • 9