Maryam Sharifi - Faculty of Physics, University of Tabriz, Tabriz, Iran
Srood Azeez Asaad - Department of Physics, Tabriz Branch Islamic Azad University, Tabriz, Iran
Hamid Pashaei Adl - Instituto de Ciencia de Materiales (ICMUV), Universidad de Valencia, C/ Catedrático José Beltrán ۲, ۴۶۹۸۰ Paterna, Spain
Habib Tajjali - Biophotonic Research Center, Tabriz Branch Islamic Azad University, Tabriz, Iran

The optical properties of graphene have been extensively studied both theoretically and experimentally for many photonic and optoelectronic applications due to its strong interaction with light over a wide range of wavelengths. A biosensor based on a defective photonic crystal consisting of three periods of alternating layers of SiO۲ and air is proposed, (SiO۲/air)/graphene/nanocomposite/graphene, according to Kretschmann configuration and used to diagnose cancer. The defect layer is a composite layer consisting of silver nanoparticles and SiO۲ dielectric, which is sandwiched between graphene layers. The influence of the number of graphene sheets and photonic crystal layers on the performance of the proposed biosensor is investigated. The results revealed that three periods are the optimum number of repetitions for photonic crystal layers, and a couple of graphene monolayers is required for improved performance of the suggested biosensor. The sensor’s sensitivity is defined as S=Δλ/RIU, with a value of ۷.۸ nm shift in the plasmon resonance wavelength per ۰.۰۱ change in refractive index unit.

Biosensor, Graphene, Nanocomposite, Kretschmann, Nanoparticles, Photonic Crystal