Macroscopic Invisibility Cloaking of Visible Light

TL;DR

This paper reports the first macroscopic visible-light invisibility cloak made from natural birefringent crystals, enabling hiding of centimeter-scale objects and advancing practical cloaking technology.

Contribution

It introduces a novel macroscopic invisibility cloak operating at visible frequencies using natural materials, overcoming previous size limitations of microfabricated cloaks.

Findings

Successfully cloaked 3D objects of centimeter scale

Operates effectively at visible light frequencies

Uses natural birefringent crystals instead of artificial metamaterials

Abstract

Invisibility cloaks of light, which used to be confined to the imagination, have now been turned into a scientific reality, thanks to the enabling theoretical tools of transformation optics and conformal mapping. Inspired by those theoretical works, the experimental realisation of electromagnetic invisibility cloaks has been reported at various electromagnetic frequencies. All the invisibility cloaks demonstrated thus far, however, have relied on nano- or micro-fabricated artificial composite materials with spatially varying electromagnetic properties, which limit the size of the cloaked region to a few wavelengths. Here we report realisation of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding three-dimensional objects of the scale of centimetres and millimetres. Our work opens avenues for future applications with macroscopic cloaking devices.