Simply and cost-effectively fabricated AuNP-based fusion spliced transmissive optical fiber LSPR probes

The transmissive optical fiber localized surface plasmon resonance (LSPR) sensor has become an effective tool in refractive index sensing because of its compact structure, high sensitivity and strong designability. However, its special structure with the sensing region in the middle of the optical fiber leads to the shortcomings of difficult preparation and poor reproducibility, which greatly restricts its application scopes. In order to solve such problem, we design gold nanoparticle (AuNP)-based fusion spliced transmissive optical fiber LSPR probes, which are fabricated via the fusion splicing between the surface modified combination tapered optical fiber and another multimode quartz optical fiber but are totally different from other fabrications of the reported transmissive optical fiber LSPR probes. The fiber probe fabrication is rather simple and cost-effective, only relying on the procedures of combination tapered optical fiber preparation, surface modification and probe fusion splicing, and except for the probe fusion splicing, the other procedures can be mass prepared thus maintaining high efficiency and good reproducibility in fiber probe fabrications. Moreover, according to the experimental verifications, the proposed fiber probes can reach rather high sensitivity in refractive index sensing with high accuracy and good stability in both static and dynamic detecting modes. Therefore, the AuNP-based fusion spliced transmissive optical fiber LSPR probe is a preferred solution for refractive index sensing and can be widely used in various applications.