A highly sensitive refractive index (RI) sensor based on the surface plasmon resonance (SPR) phenomenon is proposed and demonstrated. The sensor is composed of a quasi D-shape ten-fold photonic quasi-crystal fiber (PQF) and indium tin oxide (ITO) film. The quasi D-shape and eccentric core structure strengthen coupling between the core mode and surface plasmon polariton (SPP) mode to enhance the sensing sensitivity, while the mechanical strength of the PQF is preserved. The properties of the sensor are determined numerically and optimized by the finite element method. In the RI range of 1.40–1.44, the maximum wavelength sensitivity and average wavelength sensitivity are 62,000 nm/RIU and 26,500 nm/RIU, respectively. Meanwhile, the loss spectra show smaller full-width at half-maximum and maximum FOM of 542.5 RIU⁻¹. This novel sensor which boasts ultra-high-sensitivity and excellent FOM has large potential in the determination of liquid RIs.

提出并演示了一种基于表面等离子体共振 (SPR) 现象的高灵敏度折射率 (RI) 传感器。该传感器由准D形十倍光子准晶体光纤（PQF）和氧化铟锡（ITO）薄膜组成。准D形和偏心核心结构加强了核心模式和表面等离子体激元（SPP）模式之间的耦合，以提高传感灵敏度，同时保留了PQF的机械强度。传感器的特性由数值确定并通过有限元方法进行优化。在 1.40-1.44 的 RI 范围内，最大波长灵敏度和平均波长灵敏度分别为 62,000 nm/RIU 和 26,500 nm/RIU。同时，损耗谱显示出更小的半高全宽和 542.5 RIU ^{-1 的}最大 FOM. 这种具有超高灵敏度和优异 FOM 的新型传感器在测定液体 RI 方面具有巨大潜力。