Analysis of Tapered Fiber-Optic Surface Plasmon Resonance (SPR) Bio-Sensing Probe With the Effect of Different Taper Profiles and Metal Choices

In this article, the role of three different taper profiles along with six different metal choices on the performance parameters of tapered fiber-optic surface plasmon resonance (SPR) is discussed for the first time. Earlier, the role of different taper profiles had been discussed only in the context of the gold metal layer. In this article, the transfer matrix method has been applied to analyze the optimized metals in the context of various types of taper profiles. The comparative analysis has been performed for different taper ratios (TRs) for each metal choice. It has been found that some metals provide the SPR resonance dip in the far-infrared region and can be quite useful to achieve the terahertz (THz) sensing region without applying the other costly metals, oxides, and 2-D materials. In this article, simple three-layer linear geometry has been chosen to achieve THz sensing. This work is expected to lay the foundation for choosing better materials for the next generation of sensing applications. The results of this article can be easily extended to optimize the structure in the context of other novel materials by adding simple layers of materials.