Abstract

The growing number of serious diseases caused by ever-increasing heavy metal ions pollution have necessitated the use of ion sensors in healthcare and environment monitoring systems. Even with low concentrations heavy metal ions can cause significant harm, so ultra-sensitive on-site and label-free monitoring of heavy metal ions is of great importance. In this work, a simple, portable and high sensitivity optical fiber surface plasmon resonance (SPR) sensor is demonstrated for the detection of Hg²⁺. On the basis of the investigation of the effects of different incident angles, the optical fiber sensor adopts wedged tip probe with a 75° incident angle. The plasmonic sensor exhibits a superior refractive index bulk sensitivity of up to 13830 nm/RIU in near-infrared band, which is a further step in ultrasensitive sensing detection, compared with the traditional optical fiber SPR sensors. In addition, we validate the optical fiber sensor's performance for Hg²⁺ sensing. By self-assembling monolayer of 1,6-Hexanedithiol (HDT) on the sensing surface, the Au-coated fiber-optic probe is modified to capture Hg²⁺. The lowest detection limit is found to be 0.324 $\mathbf{ug}/\mathbf{mL}$ for the near-infrared band and the sensitivity can reach up to 0.22 nm/ $({\mathbf{ug}/\mathbf{mL}})$ . The experimental results show the excellent promise for our sensor in applications of environmental monitoring due to high sensitivity, selectivity and low-cost.

Surface plasmon resonance chemical sensor composed of a microstructured optical fiber for the detection of an ultra-wide refractive index range and gas-liquid pollutants

Wei Liu, Ying Shi, Zao Yi, Chao Liu, Famei Wang, Xianli Li, Jingwei Lv, Lin Yang, and Paul K. Chu
Opt. Express 29(25) 40734-40747 (2021)

Experimental studies on the sensitivity of the propagating and localized surface plasmon resonance-based tapered fiber optic refractive index sensors

Vivek Semwal and Banshi D. Gupta
Appl. Opt. 58(15) 4149-4156 (2019)

Surface-plasmon-resonance-based fiber-optic refractive index sensor: sensitivity enhancement

Priya Bhatia and Banshi D. Gupta
Appl. Opt. 50(14) 2032-2036 (2011)

Ultra-high sensitivity weak magnetic field detecting magnetic fluid surface plasmon resonance sensor based on a single-hole fiber

Haihao Fu, Yuying Guo, Wei Gao, Shuqin Lou, Paul K. Chu, and Zhufeng Sheng
Opt. Express 32(9) 15025-15040 (2024)

Ultra-high sensitivity SPR temperature sensor based on a helical-core fiber

Xianbin Wang, Hongchang Deng, and Libo Yuan
Opt. Express 29(14) 22417-22426 (2021)