volume | PIER Journals

Abstract

We demonstrate a novel and simple geometrical approach to cloaking a scatterer on a ground plane. We use an extremely thin dielectric metasurface to reshape the wavefronts distorted by a scatterer in order to mimic the reflection pattern of a flat ground plane. To achieve such carpet cloaking, the reflection angle has to be equal to the incident angle everywhere on the scatterer. We use a graded metasurface and calculate the required phase gradient to achieve cloaking. Our metasurface locally provides additional phase to the wavefronts to compensate for the phase difference amongst light paths induced by the geometrical distortion. We design our metasurface in the microwave range using highly sub-wavelength dielectric resonators. We verify our design by full-wave time-domain simulations using micro-structured resonators and show that results match theory very well. This approach can be applied to hide any scatterer under a metasurface of class C1 (first derivative continuous) on a ground plane not only in the microwave regime, but also at higher frequencies up to the visible.

1. Pendry, J. B., D. Schurig, and D. R. Smith, "Controlling electromagnetic fields," Science, Vol. 312, 1780-1782, 2006.
doi:10.1126/science.1125907

2. Leonhardt, U., "Optical conformal mapping," Science, Vol. 312, 1777-1780, 2006.
doi:10.1126/science.1126493

3. Schurig, D., J. J. Mock, B. J. Justice, S. A. Cummer, J. B. Pendry, A. F. Starr, and D. R. Smith, "Metamaterial electromagnetic cloak at microwave frequencies," Science, Vol. 314, 977-980, 2006.
doi:10.1126/science.1133628

4. Li, J. and J. B. Pendry, "Hiding under the carpet: A new strategy for cloaking," Phys. Rev. Lett., Vol. 101, 203901, 2008.
doi:10.1103/PhysRevLett.101.203901

5. Liu, R., C. Ji, J. J. Mock, J. Y. Chin, T. J. Cui, and D. R. Smith, "Broadband ground-plane cloak," Science, Vol. 323, 366-369, 2009.
doi:10.1126/science.1166949

6. Valentine, J., J. Li, T. Zentgraf, G. Bartal, and X. Zhang, "An optical cloak made of dielectrics," Nat. Mat., Vol. 8, 568-571, 2009.
doi:10.1038/nmat2461

7. Kallos, E., C. Argyropoulos, and Y. Hao, "Ground-plane quasicloaking for free space," Phys. Rev. A, Vol. 79, 063825, 2009.
doi:10.1103/PhysRevA.79.063825

8. Jiang, W. X., T. J. Cui, X. M. Yang, Q. Cheng, R. Liu, and D. R. Smith, "Invisibility cloak without singularity," Appl. Phys. Lett., Vol. 93, 194102, 2008.
doi:10.1063/1.3026532

9. Leonhardt, U. and T. Tyc, "Broadband invisibility by non-euclidean cloaking," Science, Vol. 323, 110-112, 2009.
doi:10.1126/science.1166332

10. Cai, W., U. K. Chettiar, A. V. Kildishev, and V. M. Shalaev, "Optical cloaking with metamaterials," Nat. Phot., Vol. 1, 224-227, 2007.
doi:10.1038/nphoton.2007.28

11. Alu, A. and N. Engheta, "Multifrequency optical invisibility cloak with layered plasmonic shells," Phys. Rev. Lett., Vol. 100, 113901, 2008.
doi:10.1103/PhysRevLett.100.113901

12. Kante, B., D. Germain, and A. de Lustrac, "Experimental demonstration of a nonmagnetic metamaterial cloak at microwave frequencies," Phys. Rev. B, Vol. 80, 201104, 2009.
doi:10.1103/PhysRevB.80.201104

13. Chen, H. and C. T. Chan, "Transformation media that rotate electromagnetic fields," Appl. Phys. Lett., Vol. 90, 241105, 2007.
doi:10.1063/1.2748302

14. Rahm, M., D. Schurig, D. A. Roberts, S. A. Cummer, D. R. Smith, and J. B. Pendry, "Design of electromagnetic cloaks and concentrators using form-invariant coordinate transformations of Maxwells equations," Photon. Nanostruct. Fundam. Appl., Vol. 6, 87-95, 2008.
doi:10.1016/j.photonics.2007.07.013

15. Jiang, W. X., T. J. Cui, Q. Cheng, J. Y. Chin, X. M. Yang, R. Liu, and D. R. Smith, "Design of arbitrarily shaped concentrators based on conformally optical transformation of nonuniform rational B-spline surfaces," Appl. Phys. Lett., Vol. 92, 264101, 2008.
doi:10.1063/1.2951485

16. Greenleaf, A., Y. Kurylev, and M. Lassas, "Electromagnetic wormholes and virtual magnetic monopoles from metamaterials," Phys. Rev. Lett., Vol. 99, 183901, 2007.
doi:10.1103/PhysRevLett.99.183901

17. Kildishev, A. V. and E. E. Narimanov, "Impedance-matched hyperlens," Opt. Lett., Vol. 32, 3432-3434, 2007.
doi:10.1364/OL.32.003432

18. O’Brien, S. and J. B. Pendry, "Magnetic activity at infrared frequencies in structured metallic photonic crystals," J. Phys. Condens. Matter, Vol. 14, 6383-6394, 2002.
doi:10.1088/0953-8984/14/25/307

19. Zhou, J., T. Koschny, M. Kafesaki, E. N. Economou, J. B. Pendry, and C. M. Soukoulis, "Saturation of the magnetic response of split-ring resonators at optical frequencies," Phys. Rev. Lett., Vol. 95, 223902, 2005.
doi:10.1103/PhysRevLett.95.223902

20. Ishikawa, A., T. Tanaka, and S. Kawata, "Negative magnetic permeability in the visible light region," Phys. Rev. Lett., Vol. 95, 237401, 2005.
doi:10.1103/PhysRevLett.95.237401

21. Kante, B., A. de Lustrac, J.-M. Lourtioz, and F. Gadot, "Engineering resonances in infrared metamaterials," Opt. Express, Vol. 16, 6774-6784, 2008.
doi:10.1364/OE.16.006774

22. Holloway, C. L., E. F. Kuester, J. A. Gordon, J. O’Hara, J. Booth, and D. R. Smith, "An overview of the theory and applications of metasurfaces: The two dimensional equivalents of metamaterials," IEEE Antennas Propagat. Mag., Vol. 54, 10-35, 2012.
doi:10.1109/MAP.2012.6230714

23. Kante, B., J.-M. Lourtioz, and A. de Lustrac, "Infrared metafilms on a dielectric substrate," Phys. Rev. B, Vol. 80, 205120, 2009.
doi:10.1103/PhysRevB.80.205120

24. Yu, N., P. Genevet, M. A. Kats, F. Aieta, J.-P. Tetienne, F. Capasso, and Z. Gaburro, "Light propagation with phase discontinuities: Generalized laws of reflection and refraction," Science, Vol. 334, 333-337, 2011.
doi:10.1126/science.1210713

25. Yu, N. and F. Capasso, "Flat optics with designer metasurfaces," Nature Materials, Vol. 13, 139-150, 2014.
doi:10.1038/nmat3839

26. Zhang, K., X. Ding, L. Zhang, and Q. Wu, "Anomalous three-dimensional refraction in the microwave region by ultra-thin high efficiency metalens with phase discontinuities in orthogonal directions," New Journal of Physics, Vol. 16, No. 10, 103020, 2014.
doi:10.1088/1367-2630/16/10/103020

27. Zhang, J., Z. L. Mei, W. R. Zhang, F. Yang, and T. J. Cui, "An ultrathin directional carpet cloak based on generalized Snell’s law," Appl. Phys. Lett., Vol. 103, 151115, 2013.
doi:10.1063/1.4824898

28. Zou, L., M. Lopez-Garc´ıa, W. Withayachumnankul, C. M. Shah, A. Mitchell, M. Bhaskaran, S. Sriram, R. Oulton, M. Klemm, and C. Fumeaux, "Spectral and angular characteristics of dielectric resonator metasurface at optical frequencies," Appl. Phys. Lett., Vol. 105, 191109, 2014.
doi:10.1063/1.4901735

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