Easily realisable physically flat lens based on quasi-conformal transformation optics

We propose easily realisable physically flat lens based on quasi-conformal transformation optical theory. To alleviate the problems of requiring complex and resonant-type metamaterials for realisation as well as for optimisation of the geometry of the transformed space, simple geometries are chosen as candidates for warped spaces. Furthermore, the paths of the rays remain conserved even in 3-dimensionally extended lens by taking an azimuthal symmetry of the calculated refractive index. Numerical simulation results verify that the proposed lens, even after structural simplification for practical implementation, performs as desired.