Open Access
All-fiber ellipsometer for nanoscale dielectric coatings
(Chinese Academy of Sciences, 2023) Imas González, José Javier; Matías Maestro, Ignacio; Del Villar, Ignacio; Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Albert, Jacques; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
Multiple mode resonance shifts in tilted fiber Bragg gratings (TFBGs) are used to simultaneously measure the thickness and the refractive index of TiO2 thin films formed by Atomic Layer Deposition (ALD) on optical fibers. This is achieved by comparing the experimental wavelength shifts of 8 TFBG resonances during the deposition process with simulated shifts from a range of thicknesses (T) and values of the real part of the refractive index (n). The minimization of an error function computed for each (n, T) pair then provides a solution for the thickness and refractive index of the deposited film and, a posteriori, to verify the deposition rate throughout the process from the time evolution of the wavelength shift data. Validations of the results were carried out with a conventional ellipsometer on flat witness samples deposited simultaneously with the fiber and with scanning electron measurements on cut pieces of the fiber itself. The final values obtained by the TFBG (n = 2.25, final thickness of 185 nm) were both within 4% of the validation measurements. This approach provides a method to measure the formation of nanoscale dielectric coatings on fibers in situ for applications that require precise thicknesses and refractive indices, such as the optical fiber sensor field. Furthermore, the TFBG can also be used as a process monitor for deposition on other substrates for deposition methods that produce uniform coatings on dissimilar shaped substrates, such as ALD.
Open Access
A comprehensive review: materials for the fabrication of optical fiber refractometers based on lossy mode resonance
(MDPI, 2020) Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA26
Lossy mode resonance based sensors have been extensively studied in recent years. The versatility of the lossy mode resonance phenomenon has led to the development of sensors based on different configurations that make use of a wide range of materials. The coating material is one of the key elements in the performance of a refractometer. This review paper intends to provide a global view of the wide range of coating materials available for the development of lossy mode resonance based refractometers.
Open Access
Route towards a label-free optical waveguide sensing platform based on lossy mode resonances
(IFSA Publishing, 2019) Ruiz Zamarreño, Carlos; Zubiate Orzanco, Pablo; Ozcariz Celaya, Aritz; Elosúa Aguado, César; Socorro Leránoz, Abián Bentor; Urrutia Azcona, Aitor; López Torres, Diego; Acha Morrás, Nerea de; Ascorbe Muruzabal, Joaquín; Vitoria Pascual, Ignacio; Imas González, José Javier; Corres Sanz, Jesús María; Díaz Lucas, Silvia; Hernáez Sáenz de Zaitigui, Miguel; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; 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,0011-1365-2017- 000117; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA26
According to recent market studies of the North American company Allied Market Research, the field of photonic sensors is an emerging strategic field for the following years and it is expected to garner $18 billion by 2021. The integration of micro and nanofabrication technologies in the field of sensors has allowed the development of new technological concepts such as lab-on-a-chip which have achieved extraordinary advances in terms of detection and applicability, for example in the field of biosensors. This continuous development has allowed that equipment consisting of many complex devices that occupied a whole room a few years ago, at present it is possible to handle them in the palm of the hand; that formerly long duration processes are carried out in a matter of milliseconds and that a technology previously dedicated solely to military or scientific uses is available to the vast majority of consumers. The adequate combination of micro and nanostructured coatings with optical fiber sensors has permitted us to develop novel sensing technologies, such as the first experimental demonstration of lossy mode resonances (LMRs) for sensing applications, with more than one hundred citations and related publications in high rank journals and top conferences. In fact, fiber optic LMR-based devices have been proven as devices with one of the highest sensitivity for refractometric applications. Refractive index sensitivity is an indirect and simple indicator of how sensitive the device is to chemical and biological species, topic where this proposal is focused. Consequently, the utilization of these devices for chemical and biosensing applications is a clear opportunity that could open novel and interesting research lines and applications as well as simplify current analytical methodologies. As a result, on the basis of our previous experience with LMR based sensors to attain very high sensitivities, the objective of this paper is presenting the route for the development of label-free optical waveguide sensing platform based on LMRs that enable to explore the limits of this technology for bio-chemosensing applications.
Open Access
Micro sized interdigital capacitor for humidity detection based on agarose coating
(2021) Vitoria Pascual, Ignacio; Armas, Dayron; Coronel Camones, Carlos Manuel; Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
A micro sized interdigital capacitor has been proposed for the detection of relative humidity. The photolithography technique enables the fabrication of fingers with a size of 10x500 um. A thin film of agarose functionalizes the sensor for humidity sensing, which improves its performance by 155 times, obtaining a sensitivity of 32.98 pF/%RH.
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
Mode transition during deposition of nanoscale ITO coatings on tilted fiber Bragg gratings
(Optica Publishing Group, 2022) Imas González, José Javier; Albert, Jacques; Del Villar, Ignacio; Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
The mode transition phenomenon is experimentally demonstrated in tilted fiber Bragg gratings (TFBG) through the deposition of an indium tin oxide (ITO) thin film employing a DC sputtering machine.
Open Access
Materials for the fabrication of optical fiber refractometers based on lossy mode resonance
(2020) Ozcariz Celaya, Aritz; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako Gobernua
Lossy mode resonances (LMR) have been studied as an exceptional phenomenon for the development of optical fiber refractometers. These sensors rely on the interaction of the light propagating through the waveguide with a thin-film fabricated onto it. The properties of such film will determine the sensitivity of the LMR to surrounding refractive index variations. The nature of the film will also play an important role on the possibilities to develop sensing applications. This thesis analyzes the use of four different materials (tin oxide, aluminum-doped zinc oxide, indium-gallium-zinc oxide and copper oxide) for the development of LMR-based refractometers. First, the optimization on the fabrication process of tin oxide coatings is described, with the purpose of maximizing the sensitivity in a refractive index range close of the fused silica (1.44). Then, materials based on zinc oxide are presented for the first time for the fabrication of LMR-based sensors: aluminum-doped zinc oxide (AZO) and indium-gallium-zinc oxide (IGZO), leading to the development of several sensors working in the visible and near-infrared wavelength range. The last material analyzed in this work is copper oxide, which presents a refractive index considerably larger than the previously studied materials. Such feature is suggested to provide a greater sensitivity of the LMR to SRI variations, promising a better performance than the one achieved with different thin-films.
Open Access
Beyond near-infrared lossy mode resonances with fluoride glass optical fiber
(Optica, 2021) Vitoria Pascual, Ignacio; Ruiz Zamarreño, Carlos; Ozcariz Celaya, Aritz; Imas González, José Javier; 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 objective of this Letter consists of the exploration of the lossy mode resonance (LMR) phenomenon beyond the nearinfrared region and specifically in the short wave infrared region (SWIR) and medium wave infrared region (MWIR). The experimental and theoretical results show for the first time, to the best of our knowledge, not only LMRs in these regions, but also the utilization of fluoride glass optical fiber associated with this phenomenon. The fabricated devices consist of a nanometric thin-film of titanium dioxide used as LMR generating material, which probed extraordinary sensitivities to external refractive index (RI) variations. RI sensitivity was studied in the SWIR and MWIR under different conditions, such as the LMR wavelength range or the order of resonance, showing a tremendous potential for the detection of minute concentrations of gaseous or biological compounds in different media.
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
Gas detection using LMR-based optical fiber sensors
(MDPI, 2018) Dreyer, Uilian José; Ozcariz Celaya, Aritz; Ascorbe Muruzabal, Joaquín; Zubiate Orzanco, Pablo; Vitoria Pascual, Ignacio; Martelli, Cicero; Cardozo da Silva, Jean Carlos; Ruiz Zamarreño, Carlos; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
This work presents a first approach to the utilization of Lossy Mode Resonance (LMR) based optical fiber sensors for gas detection. The optical sensor is based on a SnO2 thin-film fabricated onto the core of cladding removed multimode fibers (MMF). The time response of the device to four different gases (NH3, NO, CO2 and O2) was monitored obtaining the best sensitivity for NO whereas the response to NH3 revealed the best repeatability.