Tunable plasmon induced transparency in a graphene-based waveguide structure and it's applications in sensing

摘要

In this paper, we propose dynamically tunable plasmon induced transparency (PIT) in a graphene-based nanoribbon waveguide structure by changing the chemical potential of graphene. It is the direct destructive interference between the propagating plasmonic edge mode in the graphene nanoribbon waveguide and the rectangular resonators gives rise to the PIT effect. Our numerical results reveal that high tunability in the PIT transparency window can be obtained by altering the chemical potential of the graphene rectangular resonators. Moreover, a novel plasmonic refractive index sensor (RIS) has been proposed and investigated numerically based on the PIT effect in the mid-IR range. Our calculated results exhibit that large wavelength sensitivity as high as 2500 nm/RIU and a high figure of merit (FOM) of 10.50 can be achieved in this ultra-compact structure (< 0.05 μm~2). This work not only paves a new way towards the realization of graphene-based integrated nanophotonic devices, but also has important applications in multi-channel-selective filters, sensors, and slow light.