Super Resolution with Meta-Lenses

Abstract

In the previous two chapters, we described many intriguing properties in negative index materials (NIMs). One of the most striking predictions regarding NIMs as well as an exciting potential application is the “perfect lens.” Since light entering a NIM from free space will take a sharp turn at the interface, it is straightforward to see that a planar slab of NIM with sufficient thickness can act as a lens, sometimes dubbed as the Veselago lens. As depicted in Fig. 8.1c, diverging light rays from an object are negatively refracted at the first surface of the NIM slab, and the negative refraction of rays is repeated again at the second boundary. Consequently, the NIM slab creates an image within the slab and a second non-inverted image in the free space after the output interface. Compared to a conventional convex lens, the NIM lens looks quite exotic in that it does not have any axis or curvature, nor does it focus parallel rays or magnify small objects. All of these features were recognized in the seminal paper by Veselago [1]. The amazing properties of such a slab lens were first analyzed by J. B. Pendry, who pointed out that a slab with refractive index \(n = -1\) placed in vacuum allows the imaging of objects with sub-wavelength precision [2].