Desighning a Biosensor Based on Surface Plasmons Generated in Graphene Gold Grating and Study the Grating Geometry Effects on Sensitivity

Due to emergency need in early diagnosis of illnesses, the need for high performance biosensors is one of the researchers´ goals. In this paper, a structure consisting of graphene-gold grating, which formed strong plasmons in the near infrared region, was proposed to detect the refractive indexes´ changes and consequently the concentration biomolecule and, in general, all materials with a refractive index of 1.000-1.600. Sensitivity and quality factor of the proposed sensor have been calculated and the effects of structural parameters and incident light characteristics on these factors have been considered. The best result has been obtained for materials with 1.100 refractive index with 9750 quality factor. Also, the possibility of detection for some biological molecules with this sensor, such as water, glucose, MDCK and blood, with a refractive index variation of 1.000 to 1.600 has been investigated which the quality factors for these molecules have been achieved upper than 6000.