Generalized transformation optics from triple spacetime metamaterials

TL;DR

This paper extends transformation optics by allowing different transformations for field and excitation tensors, enabling new designs for non-reciprocal and indefinite materials with a geometric interpretation.

Contribution

It introduces a generalized transformation framework for spacetime metamaterials that overcomes limitations of standard transformation media.

Findings

Allows separate transformations for field and excitation tensors.

Provides geometric interpretation for non-reciprocal and indefinite materials.

Connects to electric-magnetic duality and field-transforming metamaterials.

Abstract

In this paper various extensions of the design strategy of transformation media are proposed. We show that it is possible to assign different transformed spaces to the field strength tensor (electric field and magnetic induction) and to the excitation tensor (displacement field and magnetic field), resp. In this way, several limitations of standard transformation media can be overcome. In particular it is possible to provide a geometric interpretation of non-reciprocal as well as indefinite materials. We show that these transformations can be complemented by a continuous version of electric-magnetic duality and comment on the relation to the complementary approach of field-transforming metamaterials.