Broadband subwavelength imaging with a wire medium slab loaded with graphene sheets

In this paper, we demonstrate that a wire medium slab loaded with graphene sheets enables the enhancement of the near field for the subwavelength imaging at terahertz (THz) frequencies. The unique controllable properties of graphene and structural parameters of wire medium provide significant flexibility in order to obtain tunable and broadband operating frequency range. The waveguiding and channeling properties of wire medium (WM) play a critical role in the design of a lens with low sensitivity to loss. In addition, the presence of wires improves the strong coupling of the surface plasmons supported by the upper and lower graphene monolayers. A considerable benefit of this lens is the possibility to enlarge its thickness to a significant fraction of the wavelength (>λ/6) and to maintain the subwavelength imaging with a resolution better than λ/10. These properties are studied analytically and validated against the full-wave numerical results obtained with CST Microwave Studio.