Highly Scalable Solid-core Inhibited-coupling Fiber-based Plasmonic Refractive Index Sensor

Advancements in plasmonic sensing require simultaneous detection capability that ensures large-scale detection with reduced losses. This paper introduces a novel solid-core fiber based refractive index (RI) sensor with an ultra-broad detection range. A single ring cladding with six circular tube is designed, and inhibited coupling (IC) light guiding mechanism is utilized between the core and cladding. Numerical analysis is carried out with extensive finite element modeling (FEM) through the combination of IC and surface plasmon resonance (SPR) sensing technology. Our results show low loss of $<$ 3 dB/cm across the RI detection range from 0.98 to 1.61, peaking the wavelength sensitivity (WS) of 3000 nm/RIU and figure of merit (FOM) of 120 RIU⁻¹. Our study also includes the investigation of the fabrication tolerance, fiber bending, and the use of alternative plasmonic materials, providing insights into the practical implementation capability of the proposed sensor. Our findings highlight the potential of the proposed sensor in emerging applications such as detecting air pollutants, biochemical substances, and DNA, paving the way towards bio-sensing within a lab-on-a-chip platform.