Whispery gallery mode plasmonic biosensor based on intensifying graphene layer

Abstract

This study presents a novel whispery gallery mode (WGM) biosensor based on a plasmonic nanoring structure. The biosensor's design incorporates a unique combination of gold-coated plasmonic nanoring and graphene in which graphene serves as both an intensifying and receptor layer, allowing binding and detection. According to the classification of essential biomolecules, the proposed biosensor is capable of different biomolecules detection including DNA, RNA, adenine, cytosine, guanine, thymine, and uracil. The biosensor's performance was optimized using the FEM solution method, simulating the optimal sizes of the plasmonic layer and the dimensions of the silicon nanoring. The obtained results confirm high sensitivity within the studied range of refractive index, around 105 nm/RIU. Additionally, the highest Q-factor, figure of merit and minimum detection limit are around 4179.078, 276.315 ${\mathrm{RIU}}^{-1}$and 3.619 ×${10}^{-3}$RIU, respectively. This biosensor demonstrates great potential in identifying biomolecular structures as presented in this paper, serving as a valuable tool for detecting and analyzing complex biological materials.