Optical magnetic field enhancement by strong coupling for high sensitivity sensing

We theoretically investigate the coupling effect of propagating surface plasmon polariton (PSPP) and magnetic plasmon (MP) resonance in the simple optical metamaterial, which is composed of periodic gold nanowire grating, SiO 2 spacer, and gold film on the SiO 2 substrate. By changing the period of the gold nanowire grating, the strong coupling between MP resonance and PSPP forms the hybrid modes and presents the strong anti-crossing. The interesting phenomenon of Rabi splitting as large as 97.8 meV appears. The enhanced magnetic field intensity and sensitivity of the proposed structure are up to 550 times and 585 nm/RIU, respectively, which shows great potential in the field of label-free biosensing field.