In this work, the fabrication and characterization of refractometers based on lossy mode resonances (LMR) is presented. Tin dioxide (SnO2) films deposited on optical fibers are used as the LMR supporting coatings. These resonances shift to the red as a function of the external refractive index, enabling the fabrication of robust and highly reproducible wavelength-based optical fiber refractometers. The obtained SnO2-based refractometer shows an average sensitivity of 7198 nm/refractive index unit (RIU) in the range 1.333-1.420 RIU., This work was supported by the Spanish Ministry of Economy and Competitiveness-FEDER TEC2010-17805 and
Government of Navarra research grants. Special thanks to FIDENA for the utilization of the SEM.

We report a fiber optic sensor for low levels of ammonia gas detection based on the use a Bromocresol Green (BCG) pH indicator attached to the optical fiber employing hydrophobic and gas permeable polyurethane film named Tecoflex® as attraping matrix. Highly reproducible and reversible fiber optical sensors have been achieved employing simple and short fabrication processes. The advantage for employ a BCG pH indicator is to take advantage of the basicity of ammonia exhibiting a wide spectral response (500 nm-750 nm) and shows recovery times of less than 15 s. The Tecoflex® film provides additional advantages to be measured to the sensitive area of the sensor, such as operation even in extremely dry environments, efficient transport and prevent leakage or detachment of the BCG pH indicator. The combination of the BCG pH indicator and Tecoflex® film provides a reliable and robust fiber optic ammonia gas sensor., We appreciate the support from the Consejo Nacional de Ciencia y Tecnología (CONACyT) under contract CB-2010/157866. This work was also supported by the Spanish Economy and Competitivity Ministry-FEDER TEC2010-17805

In this work, a study about the optical response of electrospun nanofiber (ENF) coatings for their use in
evanescent optical fiber sensors is presented. Several types of ENF mats composed of poly(acrylic acid)
(PAA) were developed with different ENF diameters and densities. These ENF mats were deposited onto
an optical fiber core in order to fabricate humidity evanescent optical fiber sensors. The devices were
exposed to relative humidity (RH) variations from 30% RH to 95%RH. The transfer functions of the devices
(transmitted optical power versus relative humidity) presented two well-differenced behaviors depending on the ENF diameter and the ENF mat density. The devices with lower ENF diameters and higher mat
density showed an increase in the transmitted optical power when RH increased. On the contrary, the
devices with higher ENF diameters and lower mat density showed a decrease in the transmitted optical power when RH increased. In addition to this, sensors with thinner ENF overlays, showed a higher
sensitivity. In order to study the response time of these devices, the ENFs sensors were submitted to
human breathing cycles and presented a response time around 340 ms (exhalation). In spite of the high
RH conditions of this experiment, the devices showed a recovery time around 210 ms and a negligible
hysteresis or drift with respect to the initial condition (inhalation)., This work was supported in part by the Spanish Ministry of Education and Science CICYT-FEDER TEC2010-17805 Research Grant, and a UPNA pre-doctoral research grant.

This Letter, presents the fabrication of lossy mode resonance (LMR) devices based on titanium dioxide (TiO2)/ poly(sodium 4-styrenesulfonate) (PSS) coatings deposited on side-polished D-shaped optical fibers. TiO2 thin films have been obtained by means of the layer-by-layer (LbL) self-assembly technique. LbL enables us to produce smooth and homogeneous coatings on the polished side of the fiber. This permits us to couple light from the waveguide to the TiO2-coating/external medium region at specific wavelength ranges. The generation of LMRs depends on the coating thickness, so that thicker coatings can produce more resonances. LMRs are sensitive to the external medium refractive index, which allows its utilization as refractometers. The characteristic D-shaped architecture of the devices employed in this Letter enables us to distinguish TE and TM polarizations, which had not been possible before with regular optical fibers due to their cylindrical symmetry. The results presented here show for the first time the experimental demonstration of the generation of LMRs produced by both TM and TE polarizations. More specifically, for these TiO2/PSS thin films, the TM and TM modes of the LMRs show a wavelength shift of 226 nm for the first-order LMR and 56 nm for the second-order LMR., This work was supported by the Spanish Ministry of Science and Innovation TEC2010-17805.

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., Spanish Ministry of Educationand Science, CICYT-FEDER TEC2010-17805, Fuentes DutorFoundation research grant (COIINA).

Esta tesis se centra en la síntesis de nanopartículas de plata (AgNPs) y su posterior incorporación en recubrimientos delgados usando dos métodos alternativos: el proceso de síntesis in situ (ISS) de AgNPs y la técnica de embebido capa a capa (LbL-E) de AgNPs. Un preciso control de varios parámetros tales como la forma, tamaño, estado de agregación o la distribución de las nanopartículas de plata en los recubrimientos tiene una gran influencia en la posición final de la longitud de onda de la resonancia localizada de plasmones superficiales (LSPR). Además, estas películas que incorporan nanopartículas de plata han sido estudiadas para dos aplicaciones diferentes. La primera aplicación es la fabricación de recubrimientos antibacterianos eficientes. La segunda aplicación es la fabricación de un nuevo tipo de sensores de fibra óptica basados en la incorporación de nanopartículas de plata en películas nanoestructuradas, que hace posible obtener y observar dos resonancias ópticas diferentes, (LSPR) y resonancias de modos con pérdidas (LMR), en un mismo dispositivo, This thesis is focused on the synthesis of silver nanoparticles (AgNPs) and their further incorporation into thin films using two alternative methods, the In Situ Synthesis (ISS) process and the Layer-by-Layer Embedding (LbL-E) deposition technique. A precise control of several parameters such as the shape, size, aggregation state or distribution of the AgNPs into the films has a great influence in the wavelength position of the Localized Surface Plasmon Resonance (LSPR) of the AgNPs. With this aim, two deposition methods such as sol-gel process and Layer-by-Layer (LbL) assembly have been studied and applied in order to deposit different nanocoatings based on AgNPs onto glass slides and optical fibers. In addition, these thin films that incorporate AgNPs have been studied for two different applications. The first application is the fabrication of efficient antibacterial surfaces. The second application is the implementation of new optical fiber sensors based on the incorporation of these AgNPs in nanostructured films, making possible to obtain and display two optical resonances, (LSPR) and Lossy Mode Resonances (LMR), in the same device, La realización de este tesis ha sido posible gracias a la obtención de una beca predoctoral de la Universidad Pública de Navarra (UPNA) y a las aportaciones económicas recibidas por parte del Gobierno de Navarra mediante sus programas de apoyo a la investigación, además de la colaboración de la Comisión Interministerial de Ciencia y Tecnología a través de la financiación de los proyectos CICYT fondos FEDER TEC2010-17805, Programa Oficial de Doctorado en Ingeniería de Materiales y Fabricación (RD 1393/2007), Materialen eta Fabrikazioaren Ingeniaritzako Doktoretza Programa Ofiziala (ED 1393/2007)

UPNa. Departamento de Ingeniería Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos Nanoestructurados, In this work, a comparative study about the incorporation of silver nanoparticles (AgNPs) into thin films is presented
using two alternative methods, the in situ synthesis process and the layer-by-layer embedding deposition technique.
The influence of several parameters such as color of the films, thickness evolution, thermal post-treatment, or
distribution of the AgNPs along the coatings has been studied. Thermal post-treatment was used to induce the
formation of hydrogel-like AgNPs-loaded thin films. Cross-sectional transmission electron microscopy micrographs,
atomic force microscopy images, and UV-vis spectra reveal significant differences in the size and distribution of the
AgNPs into the films as well as the maximal absorbance and wavelength position of the localized surface plasmon
resonance absorption bands before and after thermal post-treatment. This work contributes for, This work was supported by the Spanish Ministry of Economy and
Competitiveness through TEC2010-17805 Research Project, Innocampus
Program and Public University of Navarra (UPNA) research grants.

The use of Vehicular Ad-Hoc Networks (VANETs) is growing nowadays and it includes both roadside-to-vehicle communication (RVC) and inter-vehicle communication (IVC). The purpose of VANETs is to exchange useful information between vehicles and the roadside infrastructures for making an intelligent use of them. There are several possible applications for this technology like: emergency warning system for vehicles, cooperative adaptive cruise control or collision avoidance, among others. The objective of this work is to develop a VANET prototype system for urban environments using IEEE 802.15.4 compliant devices. Simulation-based values of the estimated signal strength and radio link quality values are obtained and compared with measurements in outdoor conditions to validate an implemented VANET system. The results confirm the possibility of implementing low cost vehicular communication networks operating at moderate vehicular speeds., This work has been supported by following projects Ref. IIM010566. RI1 from the Government of Navarre, Industry Department and the Ministry of Economy and Competitiveness of Spain through project TEC2010-17805.

La contaminación ambiental es la presencia de agentes físicos, químicos o biológicos presentes en el agua, suelo y aire; siendo perjudiciales para la salud de las personas, así como para la vida vegetal y animal. Las actividades económicas son esenciales para el desarrollo de la sociedad, sin embargo, muchas de estas actividades son una fuente de contaminación constante. Por ejemplo, la fuga de fluidos y gases en plantas industriales afectan negativamente a la salud e higiene para la elaboración de alimentos, bebidas, aditivos y materias primas causando un impacto ambiental y económico negativo en la industria. La búsqueda continua de métodos para el desarrollo de sistemas de medición es una característica de la evolución tecnológica de la humanidad. Las fibras ópticas presentan varias ventajas para ser empleadas en sistemas sensores; tales ventajas son: inmunidad a la interferencia electromagnética, dimensiones reducidas, ligeras, bajas pérdidas, fácil multiplexación y resistencias a la corrosión, entre otras. En general, podemos encontrar una amplia gama de aplicaciones en la industria para el desarrollo de sensores en fibra óptica. Sin embargo, en esta tesis se han seleccionado tres aplicaciones industriales de interés relevante: detección de gas amoniaco a bajas concentraciones, detección de adulteración en bebidas alcohólicas y detección de adulteración de combustibles. Se caracterizan los parámetros de los sensores desarrollados tales como la sensitividad, reversibilidad, reproducibilidad y precisión para la medición de cada tipo de sensor. Los resultados obtenidos en esta tesis serán útiles en el estudio de nuevos materiales aplicables a sensores ópticos, permitiendo la apertura a nuevas vías de investigación en el campo de los sensores en fibra óptica para aplicaciones industriales., Environmental pollution is the presence of physical, chemical or biological agents in water, soil and air which are harmful to our health, safety and welfare of the people as well as plant and animal life. Economic activities are essential to the development of society; however, many of these activities are a constant source of contamination. For example, leakage of fluids and gases in industrial plants adversely affect the health and hygiene for food processing, beverages, additives and raw materials causing serious environmental and economic impact on the general industry. The continual search for methods for developing measurement systems is a feature in the technological evolution of humankind. Optical fibers exhibit several advantages such as being immune to electromagnetic interferences, reduced dimensions, lightweight, low losses, easy multiplexation and resistant to corrosion for the development of optical fibers sensors. However, we selected three applications were the principle of operation of our sensor provides an advantage over other reported sensors: gaseous ammonia detection for low concentrations, adulteration of alcoholic beverages detection and combustibles quality control. The overall objective of this research is to design, fabricate, deploy and verify the correct operation of optical fiber structures for the identification of interesting liquid and gaseous environmental pollutants. The sensors parameters such as its sensitivity, reversibility, reproducibility and accuracy of measurement for each type of sensor are also characterized. These results obtained from this thesis would be a useful work in the study of new materials applicable to optical sensors, while opening new avenues of research in the field of optical fiber sensors for industrial applications., La realización de esta tesis ha sido posible gracias al apoyo recibido por parte del Consejo Nacional de Ciencia y Tecnología (CONACYT) bajo el contrato CB-2010/157866 y CB-2010/156529, así como de la Comisión Interministerial de Ciencia y Tecnología a través de la financiación de los proyectos CICYT fondos FEDER TEC2010-17805., Programa Oficial de Doctorado en Tecnologías de las Comunicaciones (RD 1393/2007), Komunikazioen Teknologietako Doktoretza Programa Ofiziala (ED 1393/2007)

UPNa. Departamento de Ingeniería Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos Nanoestructurados, In this paper, the influence of variable molar ratios between reducing and loading agents (1:100, 1:50, 1:20, 1:10, 1:5, 1:2, 1:1, 2:1) and between protective and loading agents (0.3:1, 0.75:1, 1.5:1, 3:1, 7.5:1, 30:1, 75:1) in the synthesis of silver nanoparticles by chemical reduction has been evaluated to obtain multicolor nanoparticles with a high stability in time. The protective agent poly(acrylic acid, sodium salt) (PAA) and reducing agent dimethylaminoborane (DMAB) play a key role in the formation of the resultant color. Evolution of the optical absorption bands of the silver nanoparticles as a function of PAA and DMAB molar ratios made it possible to confirm the presence of silver nanoparticles or clusters with a specific shape. The results reveal that a wide range of colors (violet, blue, green, brown, yellow, red, orange), sizes (from nanometer to micrometer), and shapes (cubic, rod, triangle, hexagonal, spherical) can be perfectly tuned by means of a fine control of the PAA and DMAB molar concentrations., This work was supported in part by the Spanish Ministry of Education and Science CICYT FEDER TEC2010-17805 research grant.

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., This work was supported in part by the Spanish Ministry of Education and Science CICYT FEDER TEC2010-17805 Research Grant.

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., This work was supported by the Spanish Economy and Competitiveness Ministry-Feder TEC2010-17805 Research Grant.

Acceso cerrado a este documento. No se encuentra disponible para la consulta pública. Depositado en Academica-e para cumplir con los requisitos de evaluación y acreditación académica del autor/a (sexenios, acreditaciones, etc.)., In this work, a novel fiber-optic immunoglobulin G biosensor based on lossy mode resonances is proposed. This physical phenomenon is obtained by depositing a PAH/PSS layer-by-layer thin-film on a cladding removed optical fiber. A reflective configuration is used to track the generation and response of the electromagnetic resonance in the different phases of the process. According to the results, wavelength displacements of 10 nm are visualized when detecting immunoglobulins with a response time of 12 min for a 50 μg/ml concentration.

Lossy mode resonances can be generated with certain polymeric nanostructures, such as those obtained with a multilayered assembly of poly(allylamine hydrochloride) and poly (acrylic acid). This coating is adsorbed by the electrostatic self assembly technique onto a tapered single-mode optical fiber, in order to evaluate its performance when detecting pH. According to the results reported in this work, the high sensitivity given by a tapering process in a single-mode optical fiber is increased by the effect of this kind of electromagnetic resonances. Particularly, in a pH range from 4.0 to 6.0 the overall wavelength shift of this sensor reaches 200 nm and the transmission at the resonance wavelengths can fall down to -50 dB. These data provide results which can be taken into account to detect pH with high accuracy., This work was supported by a Pre-Doctoral Research Grant of the Public University of Navarra and by the Spanish Economy and Competitivity Ministry-FEDER TEC2010-17805.

A lo largo de esta tesis se presenta el estudio y diseño de varias plataformas de guía-ondas ópticas, con el fin de ver su viabilidad a la hora de usarlas como biosensores sobre fibra óptica u otros sustratos fotónicos. En este trabajo se depositan estructuras ópticas como una fibra monomodo desnuda, un estrechamiento en fibra óptica o una fusión de fibras mono – multi – monomodo (SMS) con películas delgadas de materiales usando técnicas nanotecnológicas como el ensamblado capa a capa (LbL-assembly) o el sputtering. Además, se dedica un capítulo al estudio de microresonadores toroidales depositados por rotación (spin-coating). El objetivo es generar o mejorar las prestaciones en resolución y sensibilidad de los fenómenos resonantes que se pueden obtener en estas estructuras ópticas, para luego detectar reacciones biológicas que den lugar a un futuro diagnóstico precoz de enfermedades., Along this thesis, the study and design of several optical waveguide platforms is presented, in order to check their viability when used as biosensors based on either optical fiber or other photonic substrates. In this work, some fiber-optic-based structures such as cladding removed multimode structures, tapered single-mode fibers and single-mode – multimode – single-mode fibers are deposited with thin-films of materials, using nanotechnology-based methods such as layer-by-layer assembly (LbL-assembly) or sputtering. Moreover, a brief chapter is focused on the study of toroidal microring resonators deposited by spin-coating. The final objective is to generate or enhance the parameters of the resonant phenomena obtained in these structures, in terms of resolution and sensitivity. Then, a biological detection is addressed and characterized, to see if they are able to perform a future early diagnosis for illnesses., La realización de este trabajo ha sido posible gracias a las aportaciones económicas recibidas por parte de la Universidad Pública de Navarra (UPNA), así como del patrocinio de la UPNA y del Ministerio de Economía y Competitividad, a través de los proyectos CICYT fondos FEDER TEC2010-17805, TEC2013-43679-R e IPT-2011-1212-920000 (PMEL)., Programa Oficial de Doctorado en Ingeniería y Arquitectura (RD 1393/2007), Ingeniaritzako eta Arkitekturako Doktoretza Programa Ofiziala (ED 1393/2007)

This contribution pursues the goal of achieving an optical fibre-based platform to detect anti-gliadin antibodies (AGAs), in order to early diagnose celiac disease. To this purpose, the generation of lossy mode resonances (LMRs) in several evanescent field optical structures was studied both theoretically and experimentally. LMRs were obtained by adsorbing a polymeric thin-film onto the optical structures using the layer-by-layer assembly technique. The LMR shape depends on the geometry of the optical structure and its attenuation was controlled just by tuning the length of the device. The best performance was obtained with tapered single-mode optical fibres, which provided more than a 50% reduction in the spectral width of the LMR by using a shorter device. This improvement was successfully applied to detect anti-gliadin antibodies (AGAs) in 5 ppm concentration, what can be used to diagnose celiac disease, and shows the potential of this technology to address biosensing applications., This work was supported by a Pre-doctoral Research Grant of the Public University of Navarra and by the Spanish Economy and Competitiveness Ministry FEDER TEC2010-17805.

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., This work was supported in part by the Spanish Ministry of Education and Science-FEDER TEC2010-17805 and Government of Navarra research grants.

A universal pH indicator is used to fabricate a fiber optic ammonia sensor. The advantage of this pH indicator is that it exhibits sensitivity to ammonia over a broad wavelength range. This provides a differential response, with a valley around 500 nm and a peak around 650 nm, which allows us to perform ratiometric measurements. The ratiometric measurements provide not only an enhanced signal, but can also eliminate any external disturbance due to humidity or temperature fluctuations. In addition, the indicator is embedded in a hydrophobic and gas permeable polyurethane film named Tecoflex®. The film provides additional advantages to the sensor, such as operation in dry environments, efficient transport of the element to be measured to the sensitive area of the sensor, and prevent leakage or detachment of the indicator. The combination of the universal pH indicator and Tecoflex® film provides a reliable and robust fiber optic ammonia sensor., We appreciate the support from the Consejo Nacional de Ciencia y Tecnología (CONACyT) under contract CB-2010/157866. This work was also supported by the Spanish Economy and Competitivity Ministry-FEDER TEC2010-17805.

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., This work has been supported by a Public University of Navarre FPI grant and by the TEC2010-17805 MIC subprogram.

UPNa. Departamento de Ingeniería Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos Nanoestructurados, An inorganic short chain polymer, poly(sodium phosphate), PSP, together with poly(allylamine hydrochloride), PAH,
is used to fabricate layer-by-layer (LbL) films. The thickness, roughness, contact angle, and optical transmittance of
these films are studied depending on three parameters: the precursor solution concentrations (10−3 and 10−4 M),
the number of bilayers deposited (20, 40, 60, 80, and 100 bilayers), and the specific technique used for the LbL
fabrication (dipping or spraying). In most cases of this experimental study, the roughness of the nanofilms increases
with the number of bilayers. This contradicts the basic observations made in standard LbL assemblies where the
roughness decreases for thicker coatings. In fact, a wide range of thickness and roughness was achieved by means
of adjusting the three parameters mentioned above. For instance, a roughness of 1.23 or 205 nm root mean square
was measured for 100 bilayer coatings. Contact angles close to 0 were observed. Moreover, high optical transmittance
is also reported, above 90%, for 80 bilayer films fabricated with the 10−4 M solutions. Therefore, these multilayer
structures can be used to obtain transparent superhydrophilic surfaces., This work was supported by the Spanish Economy and Competitiveness
Ministry-FEDER TEC2010-17805.

Trabajo presentado a EUROSENSORS 2014, celebrado en Italia del 7 al 10 de septiembre de 2014., In the last 4 years, experimental evidences about the potential use of optical sensors based on Lossy Mode Resonances (LMR)
have been presented in the literature. These LMR sensors have some similarities with Surface Plasmon Resonance (SPR) sensors,
the gold standard in label-free, real-time biomolecular interaction analysis. In these new LMR sensors, if the non-metallic nanocladding
of an optical waveguide fulfills the conditions explained in this work, coupling of light to the cladding modes happens at
certain resonance wavelengths, which enables the use of LMR devices as refractometers and opens the door to diverse
applications such as in biology and proteomics research. These highly sensitive refractometers have already shown sensitivities
higher than 20,000 nm/RIU or 5x10-7 RIU and, given the youth of this field, it is expected to achieve even better values., This work was supported by the Spanish Ministry of Economy and Competitiveness-FEDER TEC2010-17805
and Government of Navarra research grants.

El desarrollo de nuevos materiales y métodos de deposición a escala nanométrica ha supuesto una auténtica revolución en muchas disciplinas de la investigación. En particular, en el campo de los sensores de fibra óptica, los recubrimientos nanoestructurados permiten generar efectos ópticos que no son apreciables mediante la utilización de materiales convencionales. El principal objetivo de esta tesis es la fabricación de nuevos sensores de humedad de fibra óptica basados en nanofibras y películas nanoestructuradas que posean propiedades antibacterianas para aplicaciones que operan en entornos de alta humedad y probacterianos. Para ello, el estudio y síntesis de nanopartículas de plata, y su posterior inclusión en los procesos de fabricación de recubrimientos como electrospinning y Layer-by-Layer han sido analizados para la fabricación de películas antibacterianas sobre fibra óptica. De esta forma, se han estudiado y desarrollado en este trabajo diferentes arquitecturas sensoras basadas en campo evanescente, resonancias basadas en plasmones superficiales localizados y modos de pérdidas, y fibras tipo Long period gratings., The development of novel materials and deposition methods on the nanometric scale has meant an important breakthrough in diverse fields. More specifically, in the field of optical fiber sensors, nanostructured coatings allow the generation of optical effects which are not appreciable with the utilization of thick films. This thesis aims to contribute to the development of optical fiber humidity sensors based on nanostructured coatings with antibacterial properties for pro-bacterial and high humidity environments. With this goal, the synthesis of silver nanoparticles and their posterior incorporation in the sensing coatings by means of techniques such as deposition methods as electrospinning and Layer-by-Layer assembly have been analyzed and studied for the fabrication of antibacterial nanocoatings onto optical fibers. Different sensing setups based on evanescent field, lossy mode resonances, localized surface plasmon resonances, and Long-Period gratings have been researched along this work to fulfill the development of such sensors., La realización de este trabajo ha sido posible gracias a la obtención de una beca predoctoral de la Universidad Pública de Navarra (UPNA), a las ayudas de movilidad de la UPNA, y a las aportaciones económicas recibidas por parte del Gobierno de Navarra mediante sus programas de apoyo a la investigación, además de la colaboración de la Comisión Interministerial de Ciencia y Tecnología a través de la financiación de los proyectos CICYT fondos FEDER TEC2010-17805, TEC2013-43679-R., Programa Oficial de Doctorado en Tecnologías de las Comunicaciones (RD 1393/2007), Komunikazioen Teknologietako Doktoretza Programa Ofiziala (ED 1393/2007)

UPNa. Departamento de Ingeniería Eléctrica y Electrónica. Laboratorio de Dispositivos Ópticos Nanoestructurados, In the present study, we show that silver nanoparticles (AgNPs) with different shape, aggregation state and color (violet, green, orange) have been successfully incorporated into polyelectrolyte multilayer thin films using the layerby- layer (LbL) assembly. In order to obtain colored thin films based on AgNPs is necessary to maintain the aggregation state of the nanoparticles, a non-trivial aspect in which this work is focused on. The use of Poly(acrylic acid, sodium salt) (PAA) as a protective agent of the AgNPs is the key element to preserve the aggregation state and makes possible the presence of similar aggregates (shape and size) within the LbLcolored films. This approach based on electrostatic interactions of the polymeric chains and the immobilization of AgNPs with different shape and size into the thin films opens up a new interesting perspective to fabricate multicolornanocomposites based on AgNPs., This work was supported in part by the Spanish Ministry of Economy and Competitiveness CICYT FEDER TEC2010-17805 research grant.

In this work we demonstrate efficient quality control of a variety of gasoline and ethanol (gasohol) blends using a multimode interference (MMI) fiber sensor. The operational principle relies on the fact that the addition of ethanol to the gasohol blend reduces the refractive index (RI) of the gasoline. Since MMI sensors are capable of detecting small RI changes, the ethanol content of the gasohol blend is easily determined by tracking the MMI peak wavelength response. Gasohol blends with ethanol contents ranging from 0% to 50% has been clearly identified using this device, which provides a linear response with a maximum sensitivity of 0.270 nm/% EtOH. The sensor can also distinguish when water incorporated in the blend has exceeded the maximum volume tolerated by the gasohol blend, which is responsible for phase separation of the ethanol and gasoline and could cause serious engine failures. Since the MMI sensor is straightforward to fabricate and does not require any special coating it is a cost effective solution for real time and in-situ monitoring of the quality of gasohol blends., The authors appreciate the support from the Consejo Nacional de Ciencia y Tecnología (CONACyT) under contract CB-2010/157866 and CB-2010/156529. This work was also supported by the Spanish Economy and Competitivity Ministry-FEDER TEC2010-17805.

This work presents the fabrication of optical fiber
refractometers based on indium tin oxide (ITO) coatings
deposited by sputtering with response in the visible spectral
region. ITO thin-films have been sputtered by employing a
rotating mechanism that enables the fabrication of smooth and
homogeneous coatings onto the optical fiber core. Fabricated
ITO coated optical fiber devices present several resonances in the
visible and near infrared 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 refractive index (RI) of the surrounding medium
it is feasible to determine the RI of the outer medium in contact
with the ITO coating by simply monitoring the chromatic
coordinates (colour change), x and y, of the visible output light, This work was supported by the Spanish Ministry of Science and Innovation TEC2010-17805.

In this work, a novel single-stage process for in
situ synthesis of Ag nanoparticles (NPs) using the layer-bylayer (LbL) technique is presented. The Ag NPs were
formed into nanotextured coatings based on sequentially
adsorbed poly(allylamine hydrochloride) (PAH) and SiO2
NPs. Such highly porous surfaces have been used in the
fabrication of highly efficient ion release films for applications such as antibacterial coatings. In this approach, the
amino groups of the PAH acted as reducing agent and made
possible the in situ formation of the Ag NPs. This reduction
reaction occurred during the LbL process as the coating was
assembled, without any further step after the fabrication and
stabilization of the multilayer film. Biamminesilver nitrate
was used as the Ag+ ion source during the LbL process and it
was successfully reduced to Ag NPs. All coatings were tested
with gram-positive and gram-negative bacterial cultures of
Escherichia coli, Staphylococcus aureus, and Lactobacillus
delbrueckii showing an excellent antimicrobial behavior
against these types of bacteria (more than 99.9% of killing
efficiency in all cases)., This work was supported in part by the Spanish
Ministry of Education and Science-CICYT-FEDER TEC2010-17805
Research Grant and the Fuentes Dutor Foundation research grant,
managed by COIINA.

An optical fiber sensor to monitor volatile organic compounds (VOCs) has been developed. The sensing material used is the organometallic [Au2Ag2(C6F5)4(NH3)2]n: its optical properties show reversible changes in presence of organic vapors. The main idea consists of using the sensing features of this material to prepare a sensor based on wavelength modulation: specifically, it meets the conditions required to induce lossy mode resonances (LMRs). The sensor works in transmission configuration, depositing the sensing compound along a segment of a plastic cladding silica (PCS) fiber where the cladding was previously removed. The method followed to deposit the sensing coating is the Layer by Layer (LbL), which allows the LMR spectral location to be tuned by means of controlling the sensing coating thickness. A spectral shift to blue is observed when the device is in presence of different organic solvents: actually, it shows a linear relation between the LMR spectral shift and the vapor concentration with a sensitivity of 0.131 nm ppm−1 from 0 to 250 ppm (v/v) of methanol. In this range, the total spectral shift is around 30 nm. The cross sensitivity to relative humidity is very low (a maximum shift of 1 nm from 40 to 60% R.H.) and negligible in the case of temperature between 20°C and 60°C., The authors would like to acknowledge the financial support from the Spanish Ministerio de Educación y Ciencia through project TEC2010-17805., Peer reviewed