Armas, DayronZubiate Orzanco, PabloRuiz Zamarreño, CarlosMatías Maestro, Ignacio2023-09-212023-09-212023Armas, D., Zubiate, P., Ruiz Zamarreño, C., Matias, I. R. (2023) Ammonia gas optical sensor based on lossy mode resonances. IEEE Sensors Letters, 7(8), 1-4. https://doi.org/10.1109/LSENS.2023.3301843.2475-147210.1109/LSENS.2023.3301843https://academica-e.unavarra.es/handle/2454/46397This letter presents the fabrication and characterization of an ammonia (NH 3) gas optical sensor based on lossy mode resonances (LMRs). A chromium (III) oxide (Cr 2 O 3) thin film deposited onto a planar waveguide was used as LMR supporting coating. The obtained LMR shows a maximum attenuation wavelength or resonance wavelength centered at 673 nm. The optical properties of the coating can be modified as a function of the presence and concentration of NH 3 in the external medium. Consequently, the refractive index of the Cr 2 O 3 thin film will change, producing a red-shift of the resonance wavelength. Obtained devices were tested for different concentrations of NH 3 as well as repetitive cycles. Concentrations as low as 10 ppbv of NH 3 were detected at room temperature. Machine learning regression models were used to mitigate the cross-sensitivity of the device under temperature and humidity fluctuations.application/pdfeng© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other work.Sensor materialsAmmonia gas sensorLossy mode resonance (LMR)Machine learningPlanar waveguidesinfo:eu-repo/semantics/article2023-09-21info:eu-repo/semantics/openAccess