Publications

Fiber-optic biosensor based on lossy mode resonances

Socorro, A.B., Villar, I.D. ,  Corres, J.M. ,  Arregui, F.J. ,  Matias, I.R.

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. 

Tapered Single-Mode Optical Fiber pH Sensor Based on Lossy Mode Resonances Generated by a Polymeric Thin-Film

Socorro, A.B., Villar, I.D. ,  Corres, J.M. ,  Arregui, F.J. ,  Matias, I.R.

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 electro-static 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 paper, 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. 

A novel luminescent optical fibre probe based on immobilized tridentate bis(phosphinic amide)...

 F.J. Sainz-Gonzalo, C. Elosua, J.F. Fernández-Sánchez, C. Popovici, I. Fernández, F.L. Ortiz, F.J. Arregui, I.R. Matias, A. Fernández-Gutiérrez

A novel optical fibre probe based on a tridentate bis(phosphinic amide)-phosphine oxide PhPO(C6H4POPhN(CH(CH3)2)2)2 (ligand 1) has been developed for the detection of europium(III) ions in water. The dip coating technique was used to deposit the ligand 1 encapsulated on a poly(vinyl chloride) membrane onto an optical fibre. The optimum deposition thickness of the membrane was 280 ± 40 nm. The sensing mechanism relies on the reaction between europium(III) ion and ligand 1, which produces a strong luminescent complex of stoichiometry 1:2 Eu(III):Ligand 1 with a maximum emission peak around 612 nm. Two different configurations, aerial and aqueous, were tested for measuring the luminescence off-line and on-line, respectively. The proposed probe showed a response time of 92 s in the aqueous configuration (in situ detection of europium(III) ions in water). The luminescence of the proposed probe displayed a power-law response for the europium(III) concentration in a broad range of concentrations of at least 5 orders of magnitude, from 10 nM to 1 mM, with a correlation coefficient (R2) of the fitted curve better than 0.99.

Lossy mode resonances dependence on the geometry of a tapered monomode optical fiber

Socorro, A.B., Villar, I.D. ,  Corres, J.M. ,  Matias, I.R.,  Arregui, F.J. ,

The geometry of a tapered single-mode optical fiber influences the formation and sensitivity of lossy mode resonances generated by the deposition of a polymeric thin-film employing the layer-by-layer electrostatic self assembly technique. In this work, several waist diameters and waist lengths of a monomode optical fiber are analyzed both experimentally and theoretically to obtain some conclusions about their influence on the behavior of this kind of devices. The transmitted optical power is studied as a function of the wavelength to estimate the sensitivity of this system. According to the results obtained, this sensitivity increases as a function of the waist length, whereas it decreases as a function of the waist diameter. What is more, depending on the combination of waist length and waist diameter, important power changes up to 45 dB can be reached at specific wavelength ranges of the electromagnetic spectrum, which can be used for accurate detection of small changes in the nanocoating properties induced by a specific analyte. This behavior can lead to sensing applications based on the combination of lossy mode resonances and tapered monomode optical fibers.

Humidity sensor based on silver nanoparticles embedded in a polymeric coating

 Pedro J. Rivero, Aitor Urrutia, Javier Goicoechea, Francisco J. Arregui, Ignacio R. Matías

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.

Influence of Waist Length in Lossy Mode Resonances Generated With Coated Tapered Single-Mode Optical Fibers.

Socorro, A.B.;  Del Villar, I.; Corres, J.M.; Arregui, F.J.; Matias, I.R.;

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.

Optical Fiber Humidity Sensors using PVdF Electrospun Nanowebs

Corres, J.M.; Rodriguez, Y.R.; Arregui, F.J.; Matias, I.R.;

In this paper, a new optical fiber humidity sensor based on PVdF nanowebs is presented. The electrospinning technique has been used to create a nanometric scale membrane onto the surface of a hollow core fiber (HCF). The fabricated sensor has demonstrated a repetitive response in the range from 50 to 70 % of relative humidity with a rise time of 100 ms. Among other applications, this sensor is intended to be used for monitoring the human breathing. Therefore, high dynamic performances are required, especially in the higher relative humidity ranges.

Lossy Mode Resonance-based pH sensor using a tapered single mode optical fiber coated with a polymeric nanostructure

Socorro, A.B.;  Del Villar, I.; Corres, J.M.; Arregui, F.J.; Matias, I.R.;

This contribution presents a pH sensor based on the combination of two technologies: tapered standard-single mode optical fiber (S-SMF) and an electromagnetic resonance phenomenon called Lossy Mode Resonance (LMR). This last phenomenon is produced by coating the optical structure with a thin polymeric film, which for specific values of the coating refractive index and thickness causes a maximum coupling of light guided in the tapered S-SMF region. Layer-by-layer electrostatic self assembly technique was used for the fabrication of a polymeric sensing nanostructure. The construction process was optimized in order to visualize the LMR behavior with a device length of 5 mm. The sensing combination produces a 250 nm wavelength-shift and a 20 dB attenuation variation of the LMR when varying the pH from 4 to 6.