CS-05: Tuning of Magnetoplasmon Coupling between Graphene Scatterers for the Optimal Design of Adjustable Metasurfaces

The purpose of this study is to extract and thoroughly analyze the resonance frequencies of magnetically-biased graphene scatterers in the THz band. Specifically, the application of an external magnetostatic bias field on graphene induces anisotropic effects caused by Lorentz forces acting on electrons. These effects reveal intriguing phenomena such as gyrotropy, non-reciprocity, and the support of magnetoplasmons [1]. Initially, a simple graphene disk is examined, and the fundamental frequencies are extracted for various applied bias fields. This process involves employing an appropriate eigenvalue formulation that enables the linear modeling of the 2D material's frequency-dispersive characteristics [2]. The extracted results for the first mode of the scatterer are depicted in Fig. 1, clearly illustrating that precise bias control can finely tune both the resonance frequency and the electromagnetic field pattern. The accurate evaluation of resonance modes in graphene scatterers enables the optimal design of more complex devices, such as metasurfaces. Specifically, tuning the bias fields appropriately modifies the device's performance based on the proximity of the operational frequency to the scatterer resonance. However, the periodic pattern of metasurfaces requires the utilization of multiple elementary cells in a periodic arrangement. Hence, our analysis extends to investigating the coupling between adjacent scatterers to assess their combined performance. Notably, the spiral electromagnetic pattern generated by the magnetically-biased scenario activates coupling in specific directions. Consequently, the metasurface exhibits increased adjustability, even in the case of a simple graphene disk scatterer, with additional degrees of freedom.References: [1] D. L.Sounas, and C. Caloz, IEEE Trans. on Microw. Theory Tech., Vol. 60, p. 901 (2012) [2] P. Lalanne, et al., J. Opt. Soc. Am. A, Vol. 36, p. 686 (2019)