On conformal lenses

TL;DR

This paper introduces conformal lenses made from gradient index materials that can omnidirectionally transform one source into multiple sources or vice versa, using conformal mapping and transmutation techniques for broadband operation.

Contribution

The paper proposes a new class of gradient index conformal lenses capable of omnidirectional source transformation, utilizing positive index materials and transmutation methods for broadband functionality.

Findings

Lenses can transform one source into multiple sources omnidirectionally.

Implementation requires only isotropic positive index materials.

Transmutation enables broadband frequency operation.

Abstract

Plane mirror can make one object into two for observers on the object's side. Yet, there seems no way to achieve the same effect for observers from all directions. In this letter, we will design a new class of gradient index lenses from multivalued optical conformal mapping. We shall call them the conformal lenses. Such lenses can transform one source into two (or even many) omnidirectionally. Like the overlapped illusion optics does, they can even transform multiple sources into one. Rather than using negative index materials, implementation here only needs isotropic positive index materials like other gradient index lenses. One obvious drawback however, is that they have singular permittivity values which restrict them to functioning at one single frequency. This however, needs not be the case when applying transmutation methods, which enable the lenses to work in a broadband frequency range.