Taguchi optimization of Surface Plasmon Resonance-Kretschmann biosensor using FDTD

This paper reports on the optimization of full-width-at-half-maximum (FWHM) of the surface plasmon resonance (SPR) curve from a graphene-based SPR biosensor. The biosensor was designed in the Kretschmann configuration which is commonly known as the most effective technique for plasmon excitation using Lumerical's finite-difference-time-domain (FDTD) analysis. The performance of the SPR biosensor can be monitored by analysing the FWHM of the SPR curves where a smaller value is desired due to a narrower resonance peak which generally corresponds to a higher transmission power resulting in a more sensitive bio-detection. To optimise the biosensor's FWHM, Taguchi's L9 orthogonal array method was utilized involving four control factors at three level values using the objective function of Smaller-the-Better (STB) signal-to-noise ratio (SNR) characteristic. The results show that the FWHM improved to 1.1261°with best settings of A3B2C3D1. The Taguchi-optimized biosensor achieved 36.98% increase in sensitivity for urea detection.