Magnetic Field Enhancement in Graphene Diabolo Nanoantenna with and without Nonlocal Effect

Zenghong Ma The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China Wei Cai The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China Lei Wang The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China Weiwei Luo The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China Xinzheng Zhang The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China Jingjun Xu The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics School, Nankai University, Tianjin, China

Graphene is made of carbon atoms arranged on a hexagons honeycomb structure [1], whose pristine form is a semimetal, but with appropriate doping it is emerging as a promising plasmonic material as well. Compared with surface plasmons in metal, graphene plasmons provide a conveniently tunable platform for strong light-matter interactions, much due to their enormous conﬁnement and relatively long propagation length [2]. In this work, we study the plasmonic properties of graphene diabolo nanoantennas (GDAs) [3], the complemental structures of bowtie aperture antenna according to Babinet’s principle. We discuss the enhancement and localization of magnetic field of GDA in mid-infrared frequency range by using the finite element method. Simulation results indicate that a smaller gap induces larger magnetic field enhancement. Specifically, a positive correlation between the polarization current density of the electric field and magnetic field intensity is obtained in local approximation, which agrees well with Ampere’s rule. In further, the magnetic field enhancement effect is calculated and compared with the nonlocal effect of graphene. What is worth mentioning is that our results present another efficient way, compare to using traditional ferromagnetic materials, to concentrate and enhance magnetic fields.

[1] Novoselov, K. S. et al. Science306,666–-669(2004).

[2] Koppens, F. H. L. et al. Nano Lett. 11, 3370 (2011)

[3] Grosjean, T. et al. Nano Lett. 11, 1009 (2011)

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