Abstract
The spectral response of a SPR (surface plasmon resonance) sensor depends on the engineering of the conducting layer. In this paper, we analyze theoretically the spectra of a D-shaped SPR PCF (photonic crystal fiber) refractive index sensor considering four different plasmonic materials: Ag, Au, Ga-doped zinc oxide (GZO) and an Ag-nanowire metamaterial. The sensing properties provided by each material and how they form the bases to design multiplasmonic resonance sensors are the focus of our discussion.

Abstract

Abstract
The growing demand for multiparameter sensors includes compact devices accompanied by simple calibration processes to distinguish the outputs from each other. This paper evaluates a scheme to determine multiple parameters of a medium using localized surface plasmon resonances (SPR) excited on a Dshaped photonic crystal fiber (PCF) partially covered by two gold layers of different thicknesses. We demonstrate that the proposed sensing platform, once customized to characterize the possible dispersive profiles of the refractive index of the analyte, also allows interrogating the temperature of a sample from a linear relationship. Since the plasmonic resonances are excited at separated and low crosstalk spectral channels, different sensing responses can be obtained simultaneously in the same location of the D-shaped PCF. These features turn out the SPR sensor a suitable tool for simultaneous monitoring of optical dispersion and temperature. © 2023 SBMO/SBMag.

Abstract
An optical fiber sensor for hydrogen detection is presented. It is based on processed fiber Bragg gratings coated with palladium thin films where its expansion due to the hydrogen adsorption is monitored as strain measurements. © Optica Publishing Group 2023, © 2023 The Author(s)

Abstract
An optical fiber pH sensor based on a long-period fiber grating was produced by coating the sensing region with two bilayers of polyethylenimine (PEI) and polyacrylic acid (PAA) using the layer-by-layer self-assembly technique. © Optica Publishing Group 2023, © 2023 The Author(s), © 2023 José M. da S. A. Pereira, João P. Mendes, José M. M. de Almeida and Luís C. C. Coelho.

Abstract
Long-term stability and high scalability are significant issues in plasmonic optical fiber sensors. This work presents a highly scalable and low-cost all-chemical approach for production of gold-coated silver thin-films, ensuring high performance and chemical stability. © Optica Publishing Group 2023, © 2023 The Authors.