Siti Azimatul Luthfiyyah, Nurul Hidayat, Latifatul Aisyah Nabila, Nur Safinatun Najah, Sunaryono Sunaryono, Hartatiek Hartatiek, Adilah Aliyatulmuna, Eka Safitri
This study aims to investigate the performance of an optical fiber salinity sensor coated with gold nanoparticles (AuNPs). The AuNPs were synthesized using the pulsed Nd:YAG laser ablation method with varying ablation times from 5 to 25 min. In this study, the optial fiber salinity sensor using a single mode fiber-no-core fiber-single mode fiber (SNS) structure was successfully developed. To increase the sensitivity of this salinity sensor, SNS were coated with AuNPs by means of self-assembly monolayer method. Characterization of the optical properties of AuNPs showed that the optimized time for AuNPs synthesis was 20 min, indicated by its optimized LSPR peak shape and the nanoparticle concentration value. Furthermore, the AuNPs exhibited a face-centered cubic (FCC) crystal structure. The morphological properties of AuNPs showed spherical shapes with average particle size of 14.43 nm could be successfully attached to the fiber surface with uniform layer formation. The AuNPs-coated SNS had a sensitivity of (0.317 ± 0.048) a.u./RIU with a LoD and LoQ of 0.507 RIU and 1.537 RIU, respectively. Immobilization of AuNPs onto SNS activated the plasmonic effect and led to an approximately 3.4-fold increase in sensitivity enhancement relative to the unmodified SNS. The plasmonic-activated optical fiber sensor had good stability in detecting salinity at detection range of 0–25%. Therefore, this study suggested a promising application of AuNPs-coated SNS for reliable salinity sensing. © 2026 Elsevier Inc.
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Jl. Semarang 5, Malang, 65145, Indonesia; Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia
