Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

An optical cloak made of dielectrics

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.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

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.

References

  1. 1

    Ward, A. J. & Pendry, J. B. Refraction and geometry in Maxwell’s equations. J. Mod. Opt. 43, 773–793 (1996).

    Article  Google Scholar 

  2. 2

    Pendry, J. B., Schurig, D. & Smith, D. R. Controlling electromagnetic fields. Science 312, 1780–1782 (2006).

    CAS  Google Scholar 

  3. 3

    Leonhardt, U. Optical conformal mapping. Science 312, 1777–1780 (2006).

    CAS  Article  Google Scholar 

  4. 4

    Leonhardt, U. Notes on conformal invisibility devices. New J. Phys. 8, 118 (2006).

    Article  Google Scholar 

  5. 5

    Smith, D. R., Padilla, W. J., Vier, D. C., Nemat-Nasser, S. C. & Schultz, S. Composite medium with simultaneously negative permeability and permittivity. Phys. Rev. Lett. 84, 4184–4187 (2000).

    CAS  Article  Google Scholar 

  6. 6

    Smith, D. R., Pendry, J. B. & Wiltshire, M. C. K. Metamaterials and negative refractive index. Science 305, 788–792 (2004).

    CAS  Article  Google Scholar 

  7. 7

    Schurig, D. et al. Metamaterial electromagnetic cloak at microwave frequencies. Science 314, 977–980 (2006).

    CAS  Article  Google Scholar 

  8. 8

    Dolin, L. S. On a possibility of comparing three-dimensional electromagnetic systems with inhomogeneous filling. Izv. Vyssh. Uchebn. Zaved. Radiofiz. 4, 964–967 (1961).

    Google Scholar 

  9. 9

    Post, E. G. Formal Structure of Electromagnetics; General Covariance and Electromagnetics (Interscience, 1962).

    Google Scholar 

  10. 10

    O’Brien, S. & Pendry, J. B. Magnetic activity at infrared frequencies in structured metallic photonic crystals. J. Phys. Condens. Matter 14, 6383–6394 (2002).

    Article  Google Scholar 

  11. 11

    Zhou, J. et al. Saturation of the magnetic response of split-ring resonators at optical frequencies. Phys. Rev. Lett. 95, 223902 (2005).

    CAS  Article  Google Scholar 

  12. 12

    Ishikawa, A., Tanaka, T. & Kawata, S. Negative magnetic permeability in the visible light region. Phys. Rev. Lett. 95, 237401 (2005).

    Article  Google Scholar 

  13. 13

    Cai, W., Chettiar, U. K., Kildishev, A. V. & Shalaev, V. M. Optical cloaking with metamaterials. Nature Photon. 1, 224–227 (2007).

    CAS  Article  Google Scholar 

  14. 14

    Alu, A. & Engheta, N. Multifrequency optical invisibility cloak with layered plasmonic shells. Phys. Rev. Lett. 100, 113901 (2008).

    Article  Google Scholar 

  15. 15

    Li, J. & Pendry, J. B. Hiding under the carpet: A new strategy for cloaking. Phys. Rev. Lett. 101, 203901 (2008).

    Article  Google Scholar 

  16. 16

    Jiang, W. X. et al. Invisibility cloak without singularity. Appl. Phys. Lett. 93, 194102 (2008).

    Article  Google Scholar 

  17. 17

    Leonhardt, U. & Tyc, T. Broadband invisibility by non-euclidean cloaking. Science 323, 110–112 (2009).

    CAS  Article  Google Scholar 

  18. 18

    Tyc, T. & Leonhardt, U. Transmutation of singularities in optical instruments. New J. Phys. 10, 115038 (2008).

    Article  Google Scholar 

  19. 19

    Liu, R. et al. Broadband ground-plane cloak. Science 323, 366–369 (2009).

    CAS  Article  Google Scholar 

  20. 20

    Linden, S. et al. Magnetic response of metamaterials at 100 Terahertz. Science 306, 1351–1353 (2004).

    CAS  Article  Google Scholar 

  21. 21

    Liu, N. et al. Three-dimensional photonic metamaterials at optical frequencies. Nature Mater. 7, 31–37 (2008).

    CAS  Article  Google Scholar 

  22. 22

    Valentine, J. et al. Three-dimensional optical metamaterial with a negative refractive index. Nature 455, 376–379 (2008).

    CAS  Article  Google Scholar 

  23. 23

    Li, J., Zhang, X. & Pendry, J. Plasmonics and Metamaterials, OSA Technical Digest (Optical Society of America, 2008) paper MMB1.

    Google Scholar 

  24. 24

    Greenleaf, A., Kurylev, Y., Lassas, M. & Uhlmann, G. Electromagnetic wormholes and virtual magnetic monopoles from metamaterials. Phys. Rev. Lett. 99, 183901 (2007).

    Article  Google Scholar 

  25. 25

    Rahm, M., Cummer, S. A., Schurig, D., Pendry, J. B. & Smith, D. R. Optical design of reflectionless complex media by finite embedded coordinate transformations. Phys. Rev. Lett. 100, 063903 (2008).

    Article  Google Scholar 

  26. 26

    Kildishev, A. V. & Shalaev, V. M. Engineering space for light via transformation optics. Opt. Lett. 33, 43–45 (2008).

    Article  Google Scholar 

  27. 27

    Levy, U. et al. Inhomogenous dielectric metamaterials with space-variant polarizability. Phys. Rev. Lett. 98, 243901 (2007).

    Article  Google Scholar 

  28. 28

    Liu, Z., Lee, H., Xiong, Y., Sun, C. & Zhang, X. Far-field optical hyperlens magnifying sub-diffraction-limited objects. Science 315, 1686 (2007).

    CAS  Article  Google Scholar 

  29. 29

    Smolyaninov, I. I., Hung, Y.-J. & Davis, C. C. Magnifying superlens in the visible frequency range. Science 315, 1699–1701 (2007).

    CAS  Article  Google Scholar 

  30. 30

    Gabrielli, L. H., Cardenas, J., Poitras, C. B. & Lipson, M. Cloaking at optical frequencies. Preprint at <http://arxiv.org/abs/0904.3508> (2009).

Download references

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.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Xiang Zhang.

Supplementary information

Supplementary Information

Supplementary Information (PDF 528 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

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

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing