Numerical investigation of a highly sensitive plasmonic refractive index sensor utilizing hexagonal lattice of photonic crystal fiber

In this paper, a gold-coated photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) technology is proposed through comprehensive numerical analysis for detection of numerous biological and biochemical analytes. The proposed sensor is designed with a simplified hexagonal geometrical structure for ease of fabrication process. Also, to facilitate the ease of sensing and real-time detection capability, the external sensing approach is employed. To investigate the performance of the proposed sensor, both the amplitude and wavelength interrogation methods are utilized. For analyte RI of 1.33 to 1.37, the sensor offers a wavelength sensitivity of 3000 nm/RIU to 13,000 nm/RIU with a maximum spectral resolution of 7.69×10-6 RIU. The proposed sensor also provides a maximum possible amplitude sensitivity of 953.23 RIU−1. In addition, the sensor provides an excellent figure of merit (FOM) with a maximum value of 228.01 RIU−1. Furthermore, the influence of the structural parameters on the sensor performance is analyzed by tuning the thickness of the gold layer, pitch, and diameter of air holes of the PCF. The proposed sensor reveals a promise to sense and detect different liquid analytes of refractive index (RI) ranging from 1.33 to 1.37 having enhanced performance characteristics.