Open Access
Lossy mode resonances biosensor for the detection of C-reactive protein
(Optica Publishing Group, 2016) Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Sánchez Zábal, Pedro; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The fabrication and characterization of optical fiber biosensor based on Lossy Mode Resonances (LMR) to detect C-reactive protein (CRP) are presented. Indium tin oxide (ITO) coatings deposited on side-polished D-shaped optical fibers are used as LMR supporting coatings. The aptamer was immobilized on the ITO film using the Layer-by-Layer (LbL) nano-assembly process. The optical fiber sensor presented shows a high selectivity and low limit detection.
Open Access
A comprehensive review of optical fiber refractometers: toward a standard comparative criterion
(Wiley, 2019) Urrutia Azcona, Aitor; Del Villar, Ignacio; Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Thanks to the peculiarities of optical fiber and its ability to be combined with nanotechnology, precise and accurate measurements of the changes in optical properties (i.e., refractive index) of the medium surrounding the fiber are becoming possible with a high degree of performance. Thus, optical fiber sensors (OFSs) are increasingly finding applications in biochemistry and biomedicine. Here, all types of optical fiber refractometers are covered, and they are classified into three main groups: interferometers, grating-based structures, and resonance-based structures (the resonance is induced by coating the optical fiber sensor with a thin film). The performance of these different structures is compared by means of the most common parameters: sensitivity, full width at half minimum or maximum, figure of merit, and quality factor. The aim here is to provide a reliable and easy-to-use tool to compare the performance of the most recent developments on fiber optic refractometers.
Open Access
Fiber-based label-free D-dimer detection for early diagnosis of venous thromboembolism
(SPIE, 2020) Zubiate Orzanco, Pablo; Urrutia Azcona, Aitor; Ruiz Zamarreño, Carlos; Fernández Irigoyen, Joaquín; Giannetti, Ambra; Baldini, Francesco; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Santamaría Martínez, Enrique; Del Villar, Ignacio; Chiavaioli, Francesco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
D-dimer is a useful diagnostic biomarker for deep vein thrombosis or pulmonary embolism, collectively referred to as venous thromboembolism (VTE). The ability to detect in real-time the amount of D-dimer with a fast and reliable method is a key step to anticipate the appearance of these diseases. The combination of fiber-optic-based platforms for biosensing with the nanotechnologies is opening up the chance for the development of in situ, portable, lightweight, versatile, reliable and high-performance optical sensing devices towards lab-on-fiber technology. The generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick absorbing metal-oxide films on special geometric-modified fibers allows measuring precisely and accurately surface refractive index changes, which are due to the binding interaction between a biological recognition element and the analyte under investigation. This approach enhances the light-matter interaction in a strong way, thus turning out to be more sensitive compared to other optical technology platforms, such as fiber gratings or surface plasmon resonance. Here, the results of a highly specific and sensitive biosensor for the detection of D-dimer based on LMR in fiber-optics are presented by monitoring in real-time the shift of the LMR related to the biomolecule interactions thanks to a conventional wavelength-interrogation system and an ad-hoc developed microfluidics. A detection limit of 100 ng/mL, a value 5-fold below the clinical cutoff value, has been attained for D-dimer spiked in human serum. The comparison of the results achieved with proteomics-based methodologies, which allows for the identification of betaand gamma-chains of fibrinogen, demonstrates the ability of our platform to specifically (>90%) recognize D-dimer.
Open Access
Sensitivity enhancement experimental demonstration using a low cutoff wavelength SMS modified structure coated with a pH sensitive film
(Elsevier, 2018) Rodríguez Rodríguez, Wenceslao Eduardo; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Rodríguez Rodríguez, Adolfo Josué; Domínguez Cruz, René; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako Gobernua
The multimode interference (MMI) effect in a single mode-multimode-single mode (SMS) can be used fordevelopment of wavelength shift detection based sensors. In this work, the focus is centered on obtainingwavelength shifts with low cutoff single mode fibers, which allows exploring the wavelength range from600 to 1000 nm, where optical sources and detectors are less expensive than at longer wavelengths. Inaddition, the application of a reduction in the fiber diameter of the SMS structure by means of HF etching,combined with the deposition of a thin-film, enables to enhance the sensitivity of the devices at thesame time the objective mentioned before is achieved. In this sense, the effect of the deposition of a pHsensitive thin-film on SMS structures with different diameters allowed attaining a maximum sensitivityof 15 nm per pH unit in the range from pH 4 to pH 6, which improves by a factor of 3 the sensitivity ofSMS sensors without etching operating at longer wavelengths.
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.
Open Access
Mode transitions and thickness measurements during deposition of nanoscale TiO2 coatings on tilted fiber Bragg gratings
(IEEE, 2022) Imas González, José Javier; Albert, Jacques; Del Villar, Ignacio; Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
The mode transition is a phenomenon observed in thin film coated long period fiber gratings (LPGs) and singlemode multimode single-mode (SMS) fibers for certain values of the coating thickness and refractive index, resulting in increased sensitivity for sensing applications. It is shown here that mode transitions occur simultaneously for a large number of mode resonances in the transmission spectra of tilted fiber Bragg gratings (TFBG) measured during the deposition of ~350nm thick TiO2 coatings by Atomic Layer Deposition (ALD). In TFBGs, the mode transition shows up as an acceleration of the resonance wavelength shift vs thickness, but without fading of the resonance amplitude. Furthermore, the results show that the mode transition for cladding modes with predominantly “TE” polarization at the cladding boundary is significantly sharper than that of predominantly “TM” polarized modes and that it occurs at a smaller coating thickness (<100 nm vs >200 nm). Finally, using a separately determined coating refractive index (2.14, by ellipsometry on witness flats deposited simultaneously) and simulations of the resonance shifts of the TFBG with coating thickness, it is demonstrated that a TFBG connected to a spectral interrogation system can be used to measure the growth of a coating on the surface of the fiber in real time.
Open Access
Experimental demonstration of lossy mode resonance generation for transverse-magnetic and transverse-electric polarizations
(Optica Publishing Group, 2013) Ruiz Zamarreño, Carlos; Zubiate Orzanco, Pablo; Sagüés García, Mikel; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
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.
Open Access
Giant sensitivity of optical fiber sensors by means of lossy moderesonance
(Elsevier, 2016) Arregui San Martín, Francisco Javier; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Zubiate Orzanco, Pablo; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
Here we show an optical refractometer with a giant sensitivity of 304,360 nm per refractive index unit(nm/RIU). This sensitivity corresponds to a resolution of 3.28 × 10−9RIU if a standard optical spectrumanalyzer with a resolution of 1 pm is used. This record sensitivity is obtained by means of a lossy moderesonance (LMR) optical fiber sensor in a surrounding media with refractive index around 1.45. Thisachievement implies that the utilization of the LMR phenomenon opens the door to devices and systemsthat can beat, in terms of sensitivity, those used currently in real-time biomolecular analysis such assurface plasmon resonance (SPR) devices.
Open Access
A comprehensive study of optical resonances in metals, dielectrics, and excitonic materials in double interface structures
(Elsevier, 2025-02-01) Imas González, José Javier; Matías Maestro, Ignacio; Del Villar, Ignacio; Ozcariz Celaya, Aritz; Vitoria Pascual, Ignacio; Ruiz Zamarreño, Carlos; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
From an optical perspective, depending on the relationship between the real (n) and imaginary (k) parts of its refractive index, three broad categories of materials can be distinguished: metals (k ¿ n), dielectrics (n ¿ k), and materials in which n ¿ k (termed here excitonic materials). The modes and optical resonances that appear in a thin film bounded by two dielectrics with similar refractive index, what we call here a double interface structure, have been widely studied in the case of metals, but not for dielectrics, or materials with n ¿ k. In this work, we propose a new approach, based on employing the phase matching condition to correlate the resonances that appear in the wavelength versus incident angle color maps of the reflected power with the modal analysis of the cross section of the structure. This analysis is performed, using an attenuated total reflection (ATR) setup, for thin film materials that belong to each of the mentioned categories: a metal (gold, Au), a dielectric (titanium dioxide, TiO2), and a material with n ¿ k (chromium, Cr). The theoretical analysis is supported with experimental results. It is demonstrated that this method enables to identify any resonance at any wavelength or incident angle, being valid for all three types of materials. Therefore, it is considered the suggested approach will help the research in these materials and in the double interface structure in the optics and photonics field.
Open Access
Micro and nanostructured materials for the development of optical fibre sensors
(MDPI, 2017) Elosúa Aguado, César; Arregui San Martín, Francisco Javier; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Corres Sanz, Jesús María; Bariáin Aisa, Cándido; Goicoechea Fernández, Javier; Hernáez Sáenz de Zaitigui, Miguel; Rivero Fuente, Pedro J.; Socorro Leránoz, Abián Bentor; Urrutia Azcona, Aitor; Sánchez Zábal, Pedro; Zubiate Orzanco, Pablo; López Torres, Diego; Acha Morrás, Nerea de; Ascorbe Muruzabal, Joaquín; Ozcariz Celaya, Aritz; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
The measurement of chemical and biomedical parameters can take advantage of the features exclusively offered by optical fibre: passive nature, electromagnetic immunity and chemical stability are some of the most relevant ones. The small dimensions of the fibre generally require that the sensing material be loaded into a supporting matrix whose morphology is adjusted at a nanometric scale. Thanks to the advances in nanotechnology new deposition methods have been developed: they allow reagents from different chemical nature to be embedded into films with a thickness always below a few microns that also show a relevant aspect ratio to ensure a high transduction interface. This review reveals some of the main techniques that are currently been employed to develop this kind of sensors, describing in detail both the resulting supporting matrices as well as the sensing materials used. The main objective is to offer a general view of the state of the art to expose the main challenges and chances that this technology is facing currently.