A quasi-3D Fano resonance cavity on optical fiber end-facet for high signal-to-noise ratio dip-and-read surface plasmon sensing

• DOI: 10.37188/lam.2022.046
• Publication Date: 2022-09-09T09:42:45Z
• Authors: Xiaqing Sun; Zeyu Lei; Hao Zhong; Chenjia He; Sihang Liu; Qingfeng Meng; Qingwei Liu; Shengfu Chen; Xiangyang Kong; Tian Yang
• Keywords: Fano resonance

Surface plasmon devices mounted at the end-facets of optical fibers are appealing candidates for rapid and point-of-care sensing applications, by offering a special dip-and-read operation mode. At present, these devices' noise-equivalent limits-of-detection lag far behind free-space counterparts, leaving them incapable most biosensing applications. Here we report quasi-3D Fano resonance cavity its fabrication method to fundamentally improve quality factor coupling efficiency fiber-coupled surface resonance. In this device, combines high Fabry-Pérot etalon plasmonic crystal cavity. The device was fabricated on planar substrate transferred single-mode fiber end-facet, which requires low-adhesion yet surface-plasmon-tunneling interface between substrate. Such an realized with nanocap-slit unit structure, consisted. A limit detection ~ 10-7 RIU experimentally obtained, allowing bovine serum albumin physical adsorption be distinguished ng mL-1 level concentrations. Therefore, breaking through long-standing signal-to-noise ratio bottleneck, work makes end-facet into one sensitivity label-free technologies. same time, it provides enabling top-down technology making 3D structures nanometer scale.