Open Access
Microstructured optical fiber sensor for soil moisture measurements
(Optical Society of America, 2018) López Aldaba, Aitor; López Torres, Diego; Campo-Bescós, Miguel; López Rodríguez, José Javier; Yerro Lizarazu, David; Elosúa Aguado, César; Arregui San Martín, Francisco Javier; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniería
A discrete sensor based on a Sn0₂-FP (Fabry-Pérot) cavity is presented and characterized in real soil conditions. Results are compared, for the first time to our knowledge, with a commercial capacitive sensor and gravimetric measurements.
Open Access
Optical sensors based on lossy-mode resonances
(Elsevier Science, 2017) Matías Maestro, Ignacio; Ascorbe Muruzabal, Joaquín; Acha Morrás, Nerea de; López Torres, Diego; Zubiate Orzanco, Pablo; Sánchez Zábal, Pedro; Urrutia Azcona, Aitor; Socorro Leránoz, Abián Bentor; Rivero Fuente, Pedro J.; Hernáez Sáenz de Zaitigui, Miguel; Elosúa Aguado, César; Goicoechea Fernández, Javier; Bariáin Aisa, Cándido; Corres Sanz, Jesús María; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Del Villar, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
Open Access
Enhancement of the sensitivity of a volatile organic compounds MOF sensor by means of its structure
(MDPI, 2019) López Torres, Diego; López Aldaba, Aitor; Elosúa Aguado, César; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this paper, we experimentally compare several core structures of Microstructured Optical Fibers (MOFs) for low-finesse Fabry-Pérot (FP) sensors. These sensors are designed for Volatile Organic Compounds (VOCs) measurements. We deposit Indium Tin Oxide (ITO) thin films by sputtering on the MOFs and different optical phase responses of the FP were measured for saturated atmospheres of ethanol. The sensitivity of the developed sensors is demonstrated to depend on the geometry and the dimensions of the MOF-cores. The sensors show recovery times under 100 s and the baselines are fully recovered after exposure to VOC.
Open Access
Enhancing sensitivity of photonic crystal fiber interferometric humidity sensor by the thickness of SnO2 thin films
(Elsevier, 2017) López Torres, Diego; Elosúa Aguado, César; Villatoro, Joel; Zubia, Joseba; Rothhardt, Manfred; Schuster, K.; Arregui San Martín, Francisco Javier; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Open Access
Real time measuring system of multiple chemical parameters using microstructured optical fibers based sensors
(IEEE, 2018) López Aldaba, Aitor; López Torres, Diego; Elosúa Aguado, César; Arregui San Martín, Francisco Javier; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; López-Amo Sáinz, Manuel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this paper, a multiplexing system for simultaneous interrogation of optical fiber sensors which measure different parameters is presented and validated. The whole system has been tested with 6 different sensing heads with different purposes: one temperature sensing head, two relative humidity sensors and three VOCs leak sensors; all of them based on microstructured optical fibers. The interrogation system uses the FFT technique to isolate each sensor's interference, enabling their simultaneous interrogation. The system interrogates all the sensors at frequencies up to 1 KHz, showing a good performance of each measurement without crosstalk between sensors. The developed system is independent of the sensors' purpose or of the multiplexing topology.
Open Access
Optical fiber sensors based on microstructured optical fibers to detect gases and volatile organic compounds: a review
(MDPI, 2020) López Torres, Diego; Elosúa Aguado, César; Arregui San Martín, Francisco Javier; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Estatistika, Informatika eta Matematika; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Estadística, Informática y Matemáticas
Since the first publications related to microstructured optical fibers (MOFs), the development of optical fiber sensors (OFS) based on them has attracted the interest of many research groups because of the market niches that can take advantage of their specific features. Due to their unique structure based on a certain distribution of air holes, MOFs are especially useful for sensing applications: on one hand, the increased coupling of guided modes into the cladding or the holes enhances significantly the interaction with sensing films deposited there; on the other hand, MOF air holes enhance the direct interaction between the light and the analytes that get into in these cavities. Consequently, the sensitivity when detecting liquids, gasses or volatile organic compounds (VOCs) is significantly improved. This paper is focused on the reported sensors that have been developed with MOFs which are applied to detection of gases and VOCs, highlighting the advantages that this type of fiber offers.
Open Access
From superhydrophilic to superhydrophobic surfaces by means of polymeric Layer-by-Layer films
(Elsevier, 2015) López Torres, Diego; Elosúa Aguado, César; Hernáez Sáenz de Zaitigui, Miguel; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Open Access
ZnO based, piezotronic optical fiber sensors for tracing volatile organic compounds
(IEEE, 2023-09-04) López Torres, Diego; Elosúa Aguado, César; Pappas, Georgios A.; Konstantaki, Maria; Klini, Argyro; Lappas, Alexandros; Arregui San Martín, Francisco Javier; Pissadakis, Stavros; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
The detection of volatile organic compounds (VOCs) is a major market and research domain, where optical sensing technologies have shown promising advances. Accordingly, ZnO has been extensively used as a transduction material in the sensing of VOCs in the vapour phase, while employing both resistive and optical detection methodologies. ZnO also exhibits significant piezoelectric properties, which in turn have been recently used in the development of piezotronic self-powered, sensing and actuating devices.
Open Access
A nanocomposite sol-gel film based on PbS quantum dots embedded into an amorphous host inorganic matrix
(MDPI, 2023) Mihail, Elisa; Sava, Bogdan Alexandru; Eftimie, Mihai; Nicoara, Adrian Ionut; Vasiliu, Ileana Cristina; Rusu, Madalin Ion; Bartha, Cristina; Enculescu, Monica; Kuncser, Andrei Cristian; Oane, Mihai; Elosúa Aguado, César; López Torres, Diego; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this study, a sol-gel film based on lead sulfide (PbS) quantum dots incorporated into a host network was synthesized as a special nanostructured composite material with potential applications in temperature sensor systems. This work dealt with the optical, structural, and morphological properties of a representative PbS quantum dot (QD)-containing thin film belonging to the Al2O3–SiO2–P2O5 system. The film was prepared using the sol-gel method combined with the spin coating technique, starting from a precursor solution containing a suspension of PbS QDs in toluene with a narrow size distribution and coated on a glass substrate in a multilayer process, followed by annealing of each deposited layer. The size (approximately 10 nm) of the lead sulfide nanocrystallites was validated by XRD and by the quantum confinement effect based on the band gap value and by TEM results. The photoluminescence peak of 1505 nm was very close to that of the precursor PbS QD solution, which demonstrated that the synthesis route of the film preserved the optical emission characteristic of the PbS QDs. The photoluminescence of the lead sulfide QD-containing film in the near infrared domain demonstrates that this material is a promising candidate for future sensing applications in temperature monitoring.
Open Access
Digital escape room project: engaging electronics for university students
(IEEE, 2024-08-01) Urrutia Azcona, Aitor; Ruete Ibarrola, Leyre; López Torres, Diego; Andueza Unanua, Ángel María; Elosúa Aguado, César; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PINNE2022-UPNA
This work proposes the implementation of a project-based learning methodology for the practical part of digital electronics subjects in the first years of undergraduate studies. Through the project called Digital Escape Room, a series of challenges and exercises are developed in a modular way that the students must solve in order to create a final design in Quartus software and demonstrate it on an FPGA-based device. The implementation of this project has allowed us to see that the academic results and the satisfaction and motivation of the students have improved significantly compared to previous years.