Refractive index sensing characteristics in a D-shaped photonic quasi-crystal fiber sensor based on surface plasmon resonance

A D-shaped photonic quasi-crystal fiber (PQF) sensor based on surface plasmon resonance is proposed for refractive index (RI) sensing. The influences of the width of the gold film, the diameter of the air holes, and the thickness of the gold film on the sensing performance are analyzed. When the RI of a liquid analyte gradually increases from 1.415 to 1.427, the average sensitivity is calculated as 10,250 nm/RIU, and the maximum sensitivity is up to 34,000 nm/RIU, which realizes the high-sensitivity sensing in the near-infrared band. The D-shaped PQF sensor proposed has great application potential in the detection of biochemical analytes and provides a new way to improve the sensing performance.