Graphene-Integrated One-Dimensional Photonic Crystal for Enhanced Optical Biosensing: A Transfer-Matrix Study

Graphene-assisted one-dimensional photonic crystals provide a route for controlling electromagnetic confinement at a sensing interface while retaining the compact geometry of multilayer optical sensors. This manuscript develops a transfer-matrix-based description of a graphene-integrated 1D photonic-crystal biosensor consisting of a BK7 coupling prism, dielectric/graphene periodic layers, a thin plasmonic metal film, an interfacial binding layer, and an aqueous sensing medium. The supplied simulation study compares conventional SPR, photonic-crystal, PC-SPR, and glass-assisted PC-SPR arrangements for Au, Ag, and Cu. Calculations are performed for TM-polarized illumination at 633 nm. For the Au case, the model uses a 45 nm metal film, a 0.34 nm graphene layer, a 470 nm PMMA layer, a 3 nm binding layer, and nine periodic units. The reported angular spectra indicate that incorporation of the photonic-crystal/glass section narrows the resonance feature. The literature source used in the supplied report also describes a 14.8-fold sensitivity enhancement for a graphene-based 1D photonic-crystal sensor; this value is a literature result and is not presented here as a new experimental measurement. The study therefore provides a reproducible numerical framework for subsequent optimization and experimental validation.