The impact of different background materials in a D-shaped photonic crystal fiber based plasmonic sensor: a comprehensive investigation

A plasmonic sensors based on photonic crystal fibers (PCF) are a pioneering platform to enhance the sensing efficiency of the sensor. And that depends on different geometrical parameters such as back ground material, plasmonic materials, pitch size, radius of the air holes and so on. So, the objective of this work is to investigate the effects of different background materials in the proposed plasmonic sensor and to enhance the sensing performance. A unique and simple plasmonic sensor using D-shaped PCF is proposed for minimize fabrication complexity. Silica, SCHOTT-FK51A, SCHOTT-BK-7, soda-lime glass, and chalcogenide glass is utilized as background material to evaluate the sensor's efficacy. Biocompatible and chemically stable gold is employed as a plasmonic material to induce the surface plasmon resonance (SPR) effect. Numerical analyses are carried out using the finite element method (FEM). The optical parameters of sensors, such as confinement loss, amplitude sensitivity, wavelength sensitivity, resolution, and figure of merit (FOM), are investigated and compared for these different materials. After optimizing various geometric parameters, the maximal wavelength sensitivity of 30,000 nm/refractive index unit (RIU) and FOM of 3000/RIU-1 is obtained for chalcogenide glass over the refractive index (RI) range of 2.31 to 2.36. The soda-lime glass has obtained a maximum resolution of 6.66 x 10(-6) RIU with 25,000 nm//RIU wavelength sensitivity in the RI range of 1.3 to 1.4. Because of its broad detection range and superior wavelength sensitivity, sensor with these background materials can used in wide range of sensing applications like chemical sensing, industrial and biomedical sensing.