s A Tunable THz Plasmonic Waveguide Based on Graphene Coated Bowtie Nanowire with High Mode Confinement

Background: A THz Plasmonic Waveguide Based on Graphene Coated Bow-tie Nanowire (TPW-GCBN) has been proposed. The waveguide characteristics are investigated by the Finite Element Method (FEM). The influence of the geometric parameters on propagation constants, electric field distributions, effective mode areas, and propagation lengths is obtained numerically. The performance tunability of TPW-GCBN is also studied by adjusting the Fermi energy. The simulation results show that TPW-GCBN has better mode confinement ability. TPW-GCBN provides a promising alternative in high-density integration of photonic circuit for the future tunable micro-nano optoelectronic devices.: Surface plasmonpolaritons based waveguides have been widely used to enhance the local electric fields. It also has the capability of manipulating electromagnetic fields on the deepsubwavelength. Objective: The waveguide characteristics of TPW-GCBN should be investigated. The tunability of TPW-GCBN should be studied by adjusting Fermi energy (FE) which can be changed by the voltage. Methods: The mode analysis and parameter sweep in Finite Element Method (FEM) were used to simulate TPW-GCBN for analyzing effective refractive index (neff), electric field distributions, normalized mode areas (Am), propagation length (Lp) and Figure of Merit (FoM). Results: At 5 THz, Aeffof λ²/14812,Lp of ~2 μm and FoM of 25 can be achieved. The simulation results show that TPW-GBN has good mode confinement ability and flexible tunability. Conclusion: TPW-GBN provides new freedom to manipulate the graphene surface plasmons, and leads to new applications in high-density integration of photonic circuits for tunable integrated optical devices.