Open Access
Humidity sensor based on silver nanopartlcles embedded in a polymeric coating
(Sciendo, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC
In this work, it is presented a novel optical fiber humidity sensor based on silver nanoparticle-loaded polymeric coatings built onto an optical fiber core. The polymeric film was fabricated using the Layer-by-Layer assembly technique. The silver nanoparticles (Ag NPs) were characterized using transmission electron microscopy (TEM and UV-VIS spectroscopy. A Localized Surface Plasmon Resonance (LSPR) attenuation band is observed when the thickness of the coating increases, and showed a very good sensitivity to Relative Humidity (RH) variations, suitable for high performance applications such as human breathing monitoring.
Open Access
Optical fiber sensors based on indium tin oxide surface plasmon resonance supporting coatings
(SPIE, 2009-10-05) Ruiz Zamarreño, Carlos; Hernáez Sáenz de Zaitigui, Miguel; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
In this work, surface plasmon resonance (SPR) based optical fiber sensors are revisited by using a transparent conductive coating, Indium Tin Oxide in our case, as the SPR supporting layer. The utilization of these coatings shifts the plasmon resonance band to the infra-red region and allows the tunability of the SPR wavelength by adjusting the film fabrication parameters. Here, we study the fabrication process of these novel devices and characterize their response to variations in the refractive index of the external medium opening the door to a wide range of applications.
Open Access
D-shape optical fiber refractometer based on TM and TE lossy mode resonances
(SPIE, 2014) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
The fabrication and characterization of an optical fiber refractometer based on Lossy Mode Resonances (LMR) is presented. TiO2/ poly (sodium 4-styrenesulfonate) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. LMRs are sensitive to the external medium refractive index and D-shaped optical fibers enable the observation of TE and TM LMR polarizations. These refractometers based on TE and TM LMR showed an average sensitivity of 2737 nm/RIU and 2893 nm/RIU respectively for a surrounding medium refractive index (SMRI) range from 1.35 to 1.41.
Open Access
Fiber-optic immunosensor based on lossy mode resonances induced by indium tin oxide thin-films
(IEEE, 2017) 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; Institute of Smart Cities - ISC
A novel immunosensor based on lossy mode resonances (LMRs) induced in optical fibers is developed in this contribution. Indium tin oxide (ITO) is sputtered on the optical substrate to generate an LMR in the transmission spectrum. Type G immunoglobulins (IgGs) are then attached to the ITO-coated fiber using (3-glycidyloxypropyl)trimethoxysilane (GPTMS). A phosphate buffer saline solution containing anti-IgGs is used to detect the biological reactions. The presented device is capable of detecting anti-IgG concentrations up to 10 nM. These results will permit the fabrication of biosensors based on a covalent attachment of bioreceptors over an LMR inducing thin-film.
Open Access
Optical fiber refractometers based on indium tin oxide coatings with response in the visible spectral region
(Elsevier, 2011) Ruiz Zamarreño, Carlos; López, S.; Hernáez Sáenz de Zaitigui, Miguel; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
This work presents the fabrication of optical fiber refractometers based on indium tin oxide (ITO) coatings with response in the visible spectral region. ITO thin-films have been sputtered by employing a rotating mechanism that enables the fabrication of smooth homogeneous coatings onto the optical fiber core. The ITO coated optical fiber devices present several resonances in the visible and infra-red region. These resonances show high optical power attenuations (more than 10 dB) in the visible spectral region, which produces changes in the colour of the output visible light. Therefore, since these resonances shift as a function of the surrounding medium refractive index (SMRI), it is feasible to determine the refractive index of the outer medium in contact with the ITO coating by simply monitoring the chromatic coordinates of the visible output light.
Open Access
D-shape optical fiber pH sensor based on lossy mode resonances (LMRs)
(IEEE, 2016-01-07) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Del Villar, Ignacio; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza
The fabrication and characterization of an optical fiber pH sensor based on Lossy Mode Resonances (LMRs) is presented. PAH/PAA polymeric thin-films fabricated onto side-polished D-shaped optical fibers are used as LMR supporting coatings. The thickness of PAH/PAA coatings can be modified as a function of the external medium pH. As a consequence of this variation, the effective refractive index of the structure will change, producing a shift of the LMR. The fabricated sensor has been used to measure pH from 4.0 to 5.0. This pH sensor showed a sensitivity of 101.3 nm per pH unit, which means a resolution of ~6×10-4 pH units by using a conventional communications Optical Spectrum Analyzer (OSA), which is an improvement over commercial pH sensors.
Embargo
Ag@Fe3O4-coated U-shaped plastic optical fiber sensor for H2S detection
(Elsevier, 2024) López Vargas, Juan David; Dante, Alex; Allil, Regina C.; Del Villar, Ignacio; Matías Maestro, Ignacio; Werneck, Marcelo M.; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work presents the fabrication of U-shaped plastic optical fiber (POF) sensors for hydrogen sulfide (H2S) detection, coated with Fe3O4 nanoparticles synthetized using the Pulsed Laser Ablation in Liquid (PLAL) technique. The Fe3O4 nanoparticles were synthetized in ultra-pure water and in silver nitrate solution, resulting in two colloidal samples with different morphological, optical, and structural properties. The Fe3O4 nanoparticles were coated onto one POF sensor, while the other sensor was coated with a nanostructure composed of Ag as the core and Fe3O4 as the shell (Ag@Fe3O4). The performance of both sensors was evaluated by exposing them to different concentrations of H2S and other gases such as CH4, H2, and CO2. All experiments were conducted at 25 °C. Results showed that the sensor coated with Ag@Fe3O4 was 12 times more sensitive to H2S compared to the sensor coated with Fe3O4, with a detection limit of 1 ppm and a rise time of 15 s. Moreover, the POF sensor coated with Ag@Fe3O4 presented high selectivity to H2S, making it a promising candidate for H2S detection in different applications. The sensor's performance was also evaluated with a relative humidity range of 20–90%, exhibiting a minimal 0.75% signal variation at 90% humidity.
Open Access
Etched LPFGs in reflective configuration for sensitivity and attenuation band depth increase
(IEEE, 2016) Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Cruz, José Luis; Rego, Gaspar; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
A reflection configuration setup for long-period fiber gratings is presented. It permits to obtain a unique band with attenuation double than that obtained in transmission configuration, which is interesting for applications where this value is reduced (e.g., the mode transition phenomenon). The method is based on the deposition of a silver mirror at the end of the optical fiber, which permits to absorb the power transmitted through cladding modes and to avoid the generation of interferometric bands. The method also solves the requirement of a precise cleave or to polish the end of the grating, a drawback present in other publications. The versatility of the setup has been proved by application of the cladding etching technique until the attenuation band corresponding with the first guided mode in the cladding is visualized in an optical spectrum analyzer. The experimental results are supported by the numerical data obtained with a method based on the exact calculation of core and cladding modes and the utilization of coupled mode theory
Open Access
Optical fiber vacuum sensor based on etched SMS structure and PDMS coating
(IEEE, 2020) Ascorbe Muruzabal, Joaquín; Fuentes Lorenzo, Omar; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Corres Sanz, Jesús María; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this work, an optical fiber vacuum sensor based on a single-mode multimode single-mode (SMS) structure coated with polydimethylsiloxane (PDMS) is studied. The SMS structure generates an interferometric pattern based on multimode interference. The structure is dip-coated with a layer of PDMS, whose optical properties change when it is subjected to varying vacuum pressure. Different strategies are applied in an attempt to improve the final performance of the sensor, such as decreasing the diameter of the fiber and modifying the properties of the coating by modifying the proportion of solvent. Decreasing the diameter of the optical fiber and using toluene as a solvent are both proved to be successful strategies for increasing the sensitivity of the sensor. The devices are studied in the 1×10-3–10 mbar range with a maximum wavelength shift of 12 nm, leading to a maximum sensitivity of 35 nm/mbar. The simplicity of the fabrication process, which can be applied to more sensitive structures, suggests that PDMS may be a good choice for the development of optical fiber vacuum sensors.
Open Access
Optical fiber vacuum sensor based on modal interferometer and PDMS coating
(IEEE, 2019) Ascorbe Muruzabal, Joaquín; Fuentes Lorenzo, Omar; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This work studies the behavior of polydimethylsiloxane (PDMS) as a transducer for optical vacuum pressure measurements. The optical structure chosen for this device is a modal interferometer achieved by splicing a coreless multimode optical fiber between two single mode fibers. Then, an etching process is applied to the obtained device, in order to decrease the diameter of the fiber and increase the sensitivity. Finally, the fiber is coated by dip-coating with a layer of PDMS, which changes its volume with pressure changes. The device has been studied in the 1x10(-3) mbar to 10 mbar range with a wavelength shift of 4 nm. A maximum sensitivity of 35 nm/mbar was obtained. The simple fabrication process, which can be applied to more sensitive structures, suggest that PDMS can be a good choice for the development of optical fiber vacuum sensors.