Open Access
A comparative study between SMS interferometers and lossy mode resonace optical fiber devices for sensing applications
(SPIE, 2015) Socorro Leránoz, Abián Bentor; Hernáez Sáenz de Zaitigui, Miguel; Del Villar, Ignacio; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Optical fiber sensors are of great interest due to their intrinsic advantages over electronic sensors. In this work, the sensing characteristics of two different and novel optical fiber devices are compared, after simultaneously depositing a thin-film using the layer-by-layer assembly deposition process. The first one is an SMS structure, formed by splicing two single-mode fiber pigtails on both sides of a coreless multimode fiber segment. This structure induces an interferometric phenomenon that generates several attenuation and transmission bands along the spectrum. These bands are sensitive to variations in the surrounding refractive index, although this sensitivity has been enhanced by a TiO2/PSS thin-film. The other device is a 40 mm uncladded segment of a 200 µm-core multimode optical fiber. When coated by a TiO2/PSS thinfilm, part of the light transmitted into the uncladded core is coupled into the thin-film, generating a lossy mode resonance (LMR). The absorption peaks due to these phenomena red-shift as long as the thin-film thickness increases or the external RI becomes higher. The performance of these devices as refractometers and relative humidity sensors are tested. Results show that the LMR-based sensor is more sensitive in both situations, in spite of its lower sensitivity. Particularly, it presents a 7-fold sensitivity enhancement when measuring surrounding medium refractive index changes and a 10-fold sensitivity enhancement when measuring environmental relative humidity. To our knowledge, this is the first time that a comparative study between SMS and LMR sensors is performed.
Open Access
An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles
(Wiley, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rodríguez, Yoany; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
This work presents an alternative approachfor fabricating electrospun submicron highly hydrophilicfiber mats loaded with silver nanoparticles. These fiber matsshow a high efficient antibacterial behavior, very attractivefor applications like wound healing and skin regenerationprocesses. The fabrication method is divided in two steps.First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD)submicron fibers were electrospun and further stabilizedusing a thermal treatment, yielding stable hydrogel-likefibers with diameters ranging from 100 nm up to severalmicrons. In the second step, silver ions were loaded into thefibers and then reduced to silver nanoparticles in-situ. Theelectrospinning parameters were adjusted to achieve thedesired properties of the fiber mat (density, size) and after-wards, the characteristics of the silver nanoparticles(amount, size, aggregation) were tuned by controlling thesilver ion loading mechanism. Highly biocide surfaces wereachieved showing more than 99.99% of killing efficiency.The two-step process improves the reproducibility and tun-ability of the fiber mats. To our knowledge, this is the firsttime that stable hydrogel fibers with a highly biocide behav-ior have been fabricated using electrospinning.
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
Optimized strain long-period fiber grating (LPFG) sensors operating at the dispersion turning point
(IEEE, 2018) Del Villar, Ignacio; Fuentes Lorenzo, Omar; Chiavaioli, Francesco; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica; Gobierno de Navarra / Nafarroako Gobernua
Two phenomena for enhancing the sensitivity of longperiod fiber gratings are combined toward an increase of the sensitivity to strain of this type of devices: the dispersion turning point (DTP) and the cladding diameter reduction by an etching process. The results prove that sensitivities up to 20 pm/με can be attained, which is a ten-fold improvement compared to the previous works. The sensitivity in the grating region, which is subjected to etching, does not depend on the order of the cladding mode responsible for the attenuation bands generated in the transmission spectrum, but on the proximity to the DTP for each mode order. On the other hand, the sensitivity to strain of the global structure, including the region without etching, can be increased for lower order modes in a perceptible way if the length of the etched region is smaller compared to the fiber region under stress. The experimental results are supported with simulations based on coupled-mode theory and on FIMMWAVE, which allows understanding the phenomena involved during the sensing process.
Open Access
AC/DC millivoltage sensor by means of ITO-coated optical fibers: towards monitoring of biosignals
(IEEE, 2019) Aginaga Etxamendi, Concepción Isabel; Socorro Leránoz, Abián Bentor; Fuentes Lorenzo, Omar; Del Villar, Ignacio; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
This contribution shows the monitoring of AC and DC millivoltage signals by means of lossy mode resonances generated by Indium Tin Oxide (ITO) on optical fibers. Sensors were obtained by sputtering ITO thin-films onto 25 mm-length segments of 200 μm bare optical fibers. Depositing a 1 μm thin-film of ITO leads to obtain reduced thin-film resistances of near 340 ohms. This allows the detection of voltage signals by monitoring the wavelength shift of the resonances. Sensitivities up to 40 nm/V can be achieved when tracking sinusoidal signals of a few cents of mV peak-to-peak. This opens the path for further research pursuing the detection of biomedical signals.
Open Access
Influence of waist length in lossy mode resonances generated with coated tapered single mode optical fibers
(IEEE, 2011) Socorro Leránoz, Abián Bentor; Del Villar, Ignacio; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work, the generation of electromagnetic resonances due to the deposition of a nanocoating on a tapered single-mode optical fiber is analyzed. The layer-by-layer technique is used to control the thickness of the nanocoating. According to the results that have been obtained, the depth of the resonance depends on the length of the waist region. Variations in the transmitted optical power of 40 dB are observed in just a few layers. This can be considered in the fabrication of both highly sensitive resonance-based sensors and optical filters.
Open Access
Increasing the sensitivity of an optic level sensor with a wavelength and phase sensitive single-mode multimode single-mode (SMS) fiber structure
(IEEE, 2017) Fuentes Lorenzo, Omar; Del Villar, Ignacio; Vento Álvarez, José Raúl; Socorro Leránoz, Abián Bentor; Gallego Martínez, Elieser Ernesto; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
The sensitivity of a liquid level sensor based on a single-mode-multimode-single-mode fiber structure has been increased by hydrofluoric acid etching. The etching process was analyzed and monitored both theoretical and experimentally, which permitted to observe that a sinusoidal spectrum can be obtained for low diameters. As an example, a 2.77 fold sensitivity increase was attained by etching from diameter 125 to 50 μm. Moreover, the sinusoidal shape of the optical spectrum permitted to monitor liquid level changes both in wavelength and phase. The cross sensitivity of the sensor to refractive index and temperature was also studied.
Open Access
Fluorescent sensors for the detection of heavy metal ions in aqueous media
(MDPI, 2019) Acha Morrás, Nerea de; Elosúa Aguado, César; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Due to the risks that water contamination implies for human health and environmental protection, monitoring the quality of water is a major concern of the present era. Therefore, in recent years several efforts have been dedicated to the development of fast, sensitive, and selective sensors for the detection of heavy metal ions. In particular, fluorescent sensors have gained in popularity due to their interesting features, such as high specificity, sensitivity, and reversibility. Thus, this review is devoted to the recent advances in fluorescent sensors for the monitoring of these contaminants, and special focus is placed on those devices based on fluorescent aptasensors, quantum dots, and organic dyes.
Open Access
Posibles nuevas vías de investigación en teoría de la comunicación a través de modelos matemáticos: análisis topológico
(Centro de Investigaciones Sociológicas, 1978) Corres Sanz, Jesús María; Burillo López, Pedro; Automática y Computación; Automatika eta Konputazioa
Uno de los pocos puntos en los que los metodólogos de las ciencias sociales están de acuerdo es el divorcio existente entre trabajo teórico y trabajo metodológico en las prácticas sociales concretas. Por otro lado, para la creación del corpus de las ciencias sociales se ha tropezado secularmente con un grave problema o inconveniente: la carencia o insuficiencia de un «lenguaje común» que permitiera el trabajo interdisciplinario de los diferentes científicos sociales. Por paradójico que parezca, este inconveniente no está siendo solucionado, únicamente, desde dentro de las ciencias sociales, sino que ha sido precisa la colaboración de otras ciencias, especialmente las ciencias exactas (física, matemáticas...). Estos dos aspectos epistemológicos de las ciencias sociales han inducido a buena parte de los investigadores sociales a abordar el estudio y análisis de las prácticas sociales a través de la Teoría de la Comunicación.
Open Access
Optical fiber immunosensors optimized with cladding etching and ITO nanodeposition
(IEEE, 2018) Cardona-Maya, Yamile; Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Corres Sanz, Jesús María; Botero-Cadavid, Juan F.; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
Etched optical fiber immunosensors, with and without ITO nanodeposition, have been developed. The performance of these immunosensors has been assessed implementing an immunoassay. The sensitivity of the mmnunosensor increased by a factor of 4 with the ITO nanocoating, whereas the limit of the detection in both types of devices was 0.2 mg/L of antigens in solution.