Orbital angular momentum-excited surface plasmon resonance for liquid refractive index sensing by photonic crystal fiber with high sensitivity and wide detection range

Abstract

With the continuous development of optical fiber sensing technology, the photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) excited by the LP0,1 mode has attracted extensive attention. In this work, an SPR PCF excited by the HE1,1 mode is designed and the various structural parameters are optimized from the perspective of the wavelength sensitivity. The phase matching, mode field distribution, wavelength sensitivity, amplitude sensitivity, structural parameter sensitivity, and figure of merit (FOM) of the PCF-SPR sensor are systematically and comprehensively analyzed numerical by the finite element method and the characteristics are compared to those of representative PCF sensors reported in recent years. The highest wavelength sensitivity of the PCF-SPR sensor is 25,800 nm / RIU, resolution is 3.87 × 10 − 6 RIU, and FOM is 289.83 RIU − 1. The excellent sensing properties suggest that the sensor has immense potential in petroleum logging, geological exploration, and other applications.