Fresnel-Fizeau drag: Invisibility conditions for all inertial observers

TL;DR

This paper demonstrates that Fresnel-Fizeau drag prevents ideal invisibility cloaks from maintaining their cloaking ability across different inertial frames, highlighting fundamental limitations due to relativistic effects.

Contribution

It analytically and through simulations shows that phase cloaking is compromised by Fresnel-Fizeau drag in all inertial frames, extending previous Doppler-based limitations.

Findings

Fresnel-Fizeau drag affects phase cloaking in all inertial frames.

Ideal amplitude cloaks cannot be perfect in all inertial frames.

Relativistic effects impose fundamental limits on invisibility devices.

Abstract

It was recently shown [Halimeh et al. arXiv:1510.06144 (to appear in Phys. Rev. A)] that as a result of the Doppler effect, inherently dispersive single-frequency ideal free-space invisibility cloaks in relative motion to an observer can only cloak light whose frequency in the cloak frame coincides with the operational frequency of the cloak, although an infinite number of such rays exist for any cloak motion. In this article, we show analytically and through ray-tracing simulations that even though this relationship can be relaxed by simplifying the ideal invisibility cloak into a broadband amplitude cloak, Fresnel-Fizeau drag uncloaks the phase of light in the inertial frame of the cloak thereby compromising its amplitude cloaking in all other inertial frames. In other words, only an invisibility device that perfectly cloaks both the amplitude and the phase of light in its own inertial frame will also (perfectly) cloak this light in any other inertial frame. The same conclusion lends itself to invisible objects that are not cloaks, such as the invisible sphere.