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An optical cloak made of dielectrics

Nature Materials volume 8, pages 568–571 (2009)Cite this article

Abstract

Invisibility devices have captured the human imagination for many years. Recent theories have proposed schemes for cloaking devices using transformation optics and conformal mapping1,2,3,4. Metamaterials5,6, with spatially tailored properties, have provided the necessary medium by enabling precise control over the flow of electromagnetic waves. Using metamaterials, the first microwave cloaking has been achieved7 but the realization of cloaking at optical frequencies, a key step towards achieving actual invisibility, has remained elusive. Here, we report the first experimental demonstration of optical cloaking. The optical ‘carpet’ cloak is designed using quasi-conformal mapping to conceal an object that is placed under a curved reflecting surface by imitating the reflection of a flat surface. The cloak consists only of isotropic dielectric materials, which enables broadband and low-loss invisibility at a wavelength range of 1,400–1,800 nm.

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Figure 1: The carpet cloak design that transforms a mirror with a bump into a virtually flat mirror.
Figure 2: Scanning electron microscope image of the carpet cloak layout.
Figure 3: Optical carpet cloaking at a wavelength of 1,540 nm.
Figure 4: Wavelength dependence of the carpet cloak.

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Acknowledgements

We acknowledge financial support from the US Department of Energy under Contract No. DE-AC02-05CH11231 and from the US Army Research Office (ARO) MURI program 50432-PH-MUR. T.Z. acknowledges a fellowship from the Alexander von Humboldt Foundation.

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Author notes

  1. Jason Valentine, Jensen Li and Thomas Zentgraf: These authors contributed equally to this work

Authors and Affiliations

  1. NSF Nano-scale Science and Engineering Center (NSEC), 3112 Etcheverry Hall, University of California, Berkeley, California 94720, USA

    Jason Valentine, Jensen Li, Thomas Zentgraf, Guy Bartal & Xiang Zhang

  2. Material Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

    Xiang Zhang

Authors
  1. Jason Valentine
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  2. Jensen Li
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  3. Thomas Zentgraf
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  4. Guy Bartal
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  5. Xiang Zhang
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Corresponding author

Correspondence to Xiang Zhang.

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Valentine, J., Li, J., Zentgraf, T. et al. An optical cloak made of dielectrics. Nature Mater 8, 568–571 (2009). https://doi.org/10.1038/nmat2461

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