On Spacetime Transformation Optics: Temporal and Spatial Dispersion

TL;DR

This paper develops a rigorous design protocol for spacetime transformation optics that accounts for dispersion, enabling more realistic and effective electromagnetic cloaking devices that consider material dispersion effects.

Contribution

It introduces a novel transformation design methodology incorporating dispersion, advancing the theoretical framework for spacetime transformation optics and cloaking applications.

Findings

Applied the methodology to an event cloak with dispersive media

Identified parameter and bandwidth constraints for dispersive cloaks

Discussed implications of dispersion on spacetime transformation design

Abstract

The electromagnetic implementation of cloaking, the hiding of objects from sight by diverting and reassembling illuminating electromagnetic fields has now been with us ten years, while the notion of hiding events is now five. Both schemes as initially presented neglected the inevitable dispersion that arises when a designed medium replaces vacuum under transformation. Here we define a transformation design protocol that incorporates both spacetime transformations and dispersive material responses in a natural and rigorous way. We show how this methodology is applied to an event cloak designed to appear as a homogeneous and isotropic but dispersive medium. The consequences for spacetime transformation design in dispersive materials are discussed, and some parameter and bandwidth constraints identified.