Amplitude-only, passive, broadband, optical spatial cloaking of very large objects

Abstract

We demonstrate three amplitude cloaks that can hide very large spatial objects over the entire visible spectrum using only passive, off-the-shelf optics. The cloaked region for all of the devices exceeds 10⁶ mm³, with the largest exceeding 10⁸ mm³. Although unidirectional, these cloaks can hide the cloaked object, even if the object is transversely illuminated or self-illuminated. Due to the small usable solid angle, but simple scaling, these cloaks may be of value in hiding small field-of-view objects such as mid- to high-earth orbit satellites from earth-based observation. Active phase front manipulation can also make these cloaks invisible to some forms of image homodyning.