Transformation optics design of a planar near field magnifier for sub-diffraction imaging

It is well established that, under certain conditions, imaging systems with either isotropic negative index, or hyperbolic (indefinite) media can achieve super-resolution. However, achieving sub-diffraction limited imaging along with uniform aberration-free magnification can be challenging. In this article, we design, simulate, and evaluate the performance of planar 2D near-field magnifying lenses, based on the transformation-optic design principle. Specifically, we investigate a grid-relaxed transformation, that results in material properties that are more amenable to implementation. We discuss possible design choices in terms of: material properties, achievable resolution enhancement, adverse effect of loss tangent, magnification factor, and other design constraints affecting the imaging performance. We also present imaging performance results for a planar, near-field, 3× magnifier operating on a standard resolution target, based on a rigorous, 3D, electromagnetic simulation. This computational intensive result was achieved using cylindrical harmonic decomposition and the 2.5D electromagnetic simulation technique. Further, we investigate and propose a path to achieve higher magnification factors using cascaded elements.