Dual planer PCF-SPR sensor based on Au-TiO₂ composite nanostructure

Abstract A novel dual planer type PCF-SPR sensor based on Au-TiO 2 composite nanostructure is proposed for the first time. In this sensor, a novel PCF structure was designed. The structure is composed of air holes of various diameters. A layer of nanogold film was platted on TiO 2 nanopillar to form Au-TiO 2 composite nanopillar. Then the Au-TiO 2 composite nanopillar was embedded into the PCF. The geometrical parameters such as PCF air hole diameters, gold layer thickness, and TiO 2 cylinder diameter were optimized, utilizing the finite-element method(FEM), and the performance of the optimized sensor was significantly improved. The maximum sensitivity was 30,000 nm RIU −1 in the refractive index range of 1.37–1.41. Unlike traditional array and planar structures, we have achieved high sensitivity refractive index sensing in PCF by using a single composite nanopillar. Due to its high sensitivity, the proposed PCF-SPR sensor is expected to find applications in biomolecular detection and chemical quantity detection.