D-type photonic crystal fiber sensor based on metal nanowire array

Abstract

A design scheme of high-sensitivity metal nanowire-based D-type dual-core photonic crystal fiber local surface plasmon resonance biosensor is proposed. The sensor consists of a polished D-type dual-core photonic crystal fiber and a metal nanowire array. The coupling strength and phase matching of the core fundamental mode and the localized surface plasmon (LSPP) mode can be adjusted by small holes in the two cores. The small holes in the two cores can also control the position of the resonance wavelength. The coupling between the core fundamental mode and the LSPP mode can be promoted by increasing the nanowire radius and the array pitch. After numerical analysis of the sensor structure using the full vector finite element method (FEM), the performance of the metal silver nanowire array is optimal. Experiments show that the sensor has a sensitivity of 7000 nm/RIU when the detection range is 1.32–1.38. And the maximum spectral sensitivity can reach 16,000 nm/RIU. Compared with the traditional coating sensor, the performance of the sensor using the metal silver nanowire array has been significantly improved. The sensor has a good application prospect in the fields of biomolecule detection and pharmaceutical composition analysis.