Invisibility cloaking without superluminal propagation

TL;DR

This paper demonstrates a new approach to invisibility cloaking that avoids the need for superluminal light speeds, overcoming a major limitation of previous Euclidean and non-Euclidean cloaking methods.

Contribution

The authors introduce a novel cloaking technique that does not require media with superluminal propagation, advancing the practical feasibility of invisibility cloaks.

Findings

Cloaking without superluminal media is achievable.

The new method simplifies the physical requirements for cloaking.

Potential for more practical invisibility devices.

Abstract

Conventional cloaking based on Euclidean transformation optics requires that the speed of light should tend to infinity on the inner surface of the cloak. Non-Euclidean cloaking still needed media with superluminal propagation. Here we show by giving an example that this is no longer necessary.