Discrete and continuous spectrum analysis: An alternative perspective on subwavelength imaging

In this paper, we establish a general framework for understanding subwavelength imaging by means of complex-plane analysis of the Sommerfeld integral for a magnetic line source over a subwavelength imaging lens. The Sommerfeld integral of the transmitted field is calculated in terms of discrete and continuous spectra. This spectral decomposition makes it possible to achieve physical insight regarding the imaging mechanisms. The results are obtained for a stack of silver slabs, an isolated wire-medium (WM) slab, and for a WM loaded with graphene sheets (GSs) and graphene patches (GPs).