Open Access
Lossy mode resonance enabling ultra-low detection limit for fibre-optic biosensors (INVITED)
(Springer, 2020) Chiavaioli, Francesco; Giannetti, Ambra; Tombelli, Sara; Trono, Cosimo; Del Villar, Ignacio; Matías Maestro, Ignacio; Zubiate Orzanco, Pablo; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Baldini, Francesco; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua, 72/2015
The combination of optical fibre-based biosensors with nanotechnologies is providing the opportunity for the development of in situ, portable, lightweight, versatile and high-sensitivity optical sensing platforms. We report on the generation of lossy mode resonances (LMRs) by means of the deposition of nm-thick SnO2 film on optical fibres. This allows measuring precisely and accurately the changes in refractive index of the fibre-surrounding medium with very high sensitivity compared to other optical technology platforms, such as long period grating or surface plasmon resonance. This approach, mixed with the use of specialty fiber structures such as Dshaped fibres, allows improving the light-matter interaction in strong way. Different imaging systems, i.e. SEM and TEM along with X-EDS tool, have been used to study the optical features of the fiber coating. The shift of the LMR has been monitored in real-time thanks to conventional wavelength interrogation system and ad hoc developed microfluidics. A big leap in performance has been attained by detecting femtomolar concentrations in human serum. The biosensor reusability has been also tested by using a solution of sodium dodecyl sulphate.
Open Access
Extraordinary sensitivity with quasi-lossy mode resonance mode transition bands in long period fiber gratings
(Elsevier, 2025-01-16) González Salgueiro, Lázaro José; Del Villar, Ignacio; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This study presents a novel sensor design utilizing a long-period fiber grating (LPFG) deposited with a TiO2 nanocoating via atomic layer deposition. The study combines theoretical simulations and experimental validation to optimize the grating period and modulation index to operate in the mode transition with a quasi-lossy mode resonance (LMR) behavior, i.e., the LPFG attenuation bands shift similarly to LMRs. This enables the achievement of a remarkable sensitivity of 78 nm/nm, allowing for the detection of sub-angstrom variations in film thickness, which is critical for applications in semiconductor manufacturing. Our setup facilitates continuous monitoring of the transmission spectrum, enabling real-time adjustments during deposition to maximize sensitivity. As proof of concept for the applicability of the sensor as a refractive index sensor, we demonstrated exceptional sensitivity for nitrogen detection, achieving around 10,000 nm/RIU, with a figure of merit of 200. This marks one the highest sensitivities reported for optical fiber gas sensors and suggests this technology could revolutionize the field duet to its simplicity in terms of sensor design.
Open Access
Sensors based on thin-film coated cladding removed multimode optical fiber and single-mode multimode single-mode fiber: a comparative study
(Hindawi Publishing Corporation, 2015) Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Hernáez Sáenz de Zaitigui, Miguel; Corres Sanz, Jesús María; Ruiz Zamarreño, Carlos; Sánchez Zábal, Pedro; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Two simple optical fibre structures that do not require the inscription of a grating, a cladding removed multimode optical fibre (CRMOF) and a single-mode multimode single-mode structure (SMS), are compared in terms of their adequateness for sensing once they are coated with thin-films.The thin-film deposited (TiO2/PSS) permits increasing the sensitivity to surrounding medium refractive index. The results obtained can be extrapolated to other fields such as biological or chemical sensing just by replacing the thin-film by a specific material.
Open Access
High sensitivity lossy-mode resonance refractometer using low refractive index PFA planar waveguide
(Elsevier, 2023) Domínguez Rodríguez, Ismel; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Ascorbe Muruzabal, Joaquín; Del Villar, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
In this work a new strategy to improve the sensitivity of refractometers based on lossy-mode resonances has been proved. The proximity of the PFA (tetrafluoroethylene-perfluoro polymer) substrate refractive index to that of water has permitted to implement an optical refractometer with a sensitivity of 41,034 nm per refractive index unit (nm/RIU) for refractive indices ranging from 1.3318 to 1.3347. The work is supported with both theoretical and experimental results. This high sensitivity can be used for the development of LMR based chemical sensors and biosensors, where a low limit of detection is required, with the additional advantage of a simple disposable planar configuration.
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
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.
Embargo
Experimental study of sensing performance using hyperbolic mode resonances
(Elsevier, 2025-01-01) Matías Maestro, Ignacio; Del Villar, Ignacio; Corres Sanz, Jesús María; González Salgueiro, Lázaro José; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Surface plasmon resonance (SPR) and lossy mode resonance (LMR) are prominent sensing mechanisms utilized across various fields. The Kretschmann configuration is commonly employed for SPR, while LMR is favored in planar waveguides or optical fibers due to high incidence angles. Recently, hyperbolic mode resonance (HMR) has emerged as a hybrid approach, combining metallic and dielectric thin films. This study explores the impact of incidence angle on HMR using the Kretschmann configuration. Four samples with varying gold (Au) and tin dioxide (SnO2) layer thicknesses were fabricated and characterized using Atomic Force Microscopy (AFM). Experimental setups employed the Kretschmann configuration for reflectance spectrum analysis. Results indicate enhanced sensitivity and figure of merit (FoM) with an additional SnO2 layer compared to the case without SnO2. Particularly with a 36 nm Au thickness the sensitivity doubles and the FoM improves by 16 %. Numerical simulations validate these findings, confirming the optimized performance of HMR for specific layer thicknesses and incidence angles.
Open Access
Fiber-based early diagnosis of venous thromboembolic disease by label-free D-dimer detection
(Elsevier, 2019) Zubiate Orzanco, Pablo; Urrutia Azcona, Aitor; Ruiz Zamarreño, Carlos; Egea Urra, Josune; Fernández Irigoyen, Joaquín; Giannetti, Ambra; Baldini, Francesco; Díaz Lucas, Silvia; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Santamaría Martínez, Enrique; Chiavaioli, Francesco; Del Villar, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
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. Here, the results of a highly specific and sensitive biosensor for the detection of D-dimer based on lossy mode resonance in fiber optics are presented. The unique features of specialty fibers in light management integrated with microfluidics allow detecting D-dimer in human serum with a detection limit of 100 ng/mL, a value 5-fold below the clinical cutoff value. Comparison of the results achieved with mass-spectrometry-based proteomics, which allows for the identification of beta- and gamma-chains of fibrinogen, demonstrates the ability of our platform to specifically (>90%) recognize D-dimer. Therefore, this technology potentially represents a paradigm shift in the development of a simple, high-specificity and label-free biosensing platform, which can be applied to speed up diagnostic healthcare processes of venous thromboembolism toward an early diagnostic and personalized treatment system.
Open Access
Lossy mode resonance based microfluidic platform developed on planar waveguide for biosensing applications
(MDPI, 2022) Benítez Pérez, Melanys; Zubiate Orzanco, Pablo; Del Villar, Ignacio; Socorro Leránoz, Abián Bentor; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The development of resonance phenomena-based optical biosensors has gained relevance in recent years due to the excellent optical fiber properties and progress in the research on materials and techniques that allow resonance generation. However, for lossy mode resonance (LMR)-based sensors, the optical fiber presents disadvantages, such as the need for splicing the sensor head and the complex polarization control. To avoid these issues, planar waveguides such as coverslips are easier to handle, cost-effective, and more robust structures. In this work, a microfluidic LMR-based planar waveguide platform was proposed, and its use for biosensing applications was evaluated by detecting anti-immunoglobulin G (anti-IgG). In order to generate the wavelength resonance, the sensor surface was coated with a titanium dioxide (TiO2) thin-film. IgG antibodies were immobilized by covalent binding, and the detection assay was carried out by injecting anti-IgG in PBS buffer solutions from 5 to 20 μg/mL. The LMR wavelength shifted to higher values when increasing the analyte concentration, which means that the proposed system was able to detect the IgG/anti-IgG binding. The calibration curve was built from the experimental data obtained in three repetitions of the assay. In this way, a prototype of an LMR-based biosensing microfluidic platform developed on planar substrates was obtained for the first time
Open Access
Generation of lossy mode resonances in planar waveguides toward development of humidity sensors
(IEEE, 2019) Fuentes Lorenzo, Omar; Corres Sanz, Jesús María; Matías Maestro, Ignacio; Del Villar, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Lossy mode resonances (LMRs) are typically obtained with optical fibre. The Kretschmann configuration is an alternative but LMRs are generated with angles approaching grazing incidence. In this work, a new setup is explored, based on the lateral incidence of light on conventional planar waveguides such as glass slides or coverslips. Indium tin oxide was deposited onto both types of waveguides generating LMRs. The results of the simulations carried out agree well with the experimental results. As an example of the potential of this new and simple optical configuration, a humidity sensor with a sensitivity of 0.212 nm/% relative humidity (RH) in the range from 65% to 90% of RH was developed, which expedites the development of other types of sensors already explored with LMR-based optical fibre sensors.