Au-MgF 2 -Coated Photonic Crystal Fiber Surface Plasmon Resonance Sensor with High FOM

A surface plasmon resonance (SPR) sensor composed of photonic crystal fibers (PCFs) is designed for refractive index (RI) sensing with a high figure of merit (FOM). The dual Au-MgF 2 layer is covered on the double-side polished D-type PCF to stimulate SPR. Our numerical analysis reveals that the maximum wavelength sensitivity and amplitude sensitivity of the PCF-SPR sensor are 59,000 nm/RIU and 6076 RIU −1 , respectively, in the RI range of 1.25 ~ 1.43. The maximum FOM is 2033 RIU −1 and the resolution is 1.69 × 10 −6 . The results provide guidance and insights into the design of PCF-SPR sensors with high FOM.