Invisible Cloak Made of Metamaterial

1. Invisible Cloak Made of Metamaterial B96901128 王郁翔

2. Outline • 1. Basic Concepts • 2. Free-Space Cloak in 2006 • 3. Carpet Cloak in 2008 • 4. Carpet Cloak in 2009 • 5. Conclusions • 6. References

3. Basic Concepts • Transformation optics and quasiconformal mapping. • Inhomogeneous material—curved space, apply Fermat’s principle. • Cloaking, concentrating, rotating, bending, black hole,..

4. Equivalence of two space

5. Free-Space Cloak in 2006 • First proposed by Pendry[1]and Leonhardt[2].theorem in book[3-4]

6. Free-Space Cloak in 2006

7. Free-Space Cloak in 2006 • Used reduced parameter to realized in microwave frequency[5].

8. Free-Space Cloak in 2006 • Drawback • 1. Singular parameter • 2. Need to use resonant structure, narrow bandwidth and high loss. • 3. Anisotropic • Hard to fabricate and applied.

9. Carpet Cloak in 2008 • Instead crushed cloaked object to a point, we can also crushed to a line or a sheet(carpet cloak). • Broad-band, low loss and isotropic, easy to fabricate. • Hide the tank or the aircraft on the ground.

10. Carpet Cloak in 2008 • Proposed by Pendry[6]

11. Carpet Cloak in 2008 • The optimal map is generated by minimizing the Modified-Liao functional upon slipping BC[3]. • Choose smallest anisotropy factor(1.042).

12. Carpet Cloak in 2008 • Realized in microwave frequency[7] and optic frequency[8-9].

13. Carpet Cloak in 2008

14. Carpet Cloak in 2008 • Drawback • 1.Carpet cloak has very large size (height ratio=65.7) • 2.Background is not free space. • Therefore, T.J.Cui proposed a compact-sized broadband carpet cloak[10].

15. Carpet Cloak in 2009 • Set background to free space, and use n=1 to replace the region where n<1. • Height ratio from 65.7 to 7.33.

16. Carpet Cloak in 2009

17. Carpet Cloak in 2009 • Different h, different ε.

18. Carpet Cloak in 2009 • Measure at different frequency.

19. Carpet Cloak in 2009 • Compare full-parameter carpet cloak and simplified carpet cloak(simulation).

20. Directive Free-Space Cloak

21. Directive Free-Space Cloak • Simulate and measure at different frequency.

22. Directive Free-Space Cloak

23. Conclusions • Compact-sized, broadband carpet cloak is developed, and it represents a major step towards real applications of invisibility devices.

24. Reference • [1] J. B. Pendry, D. Schurig, and D. R. Smith, “Controlling electromagnetic fields,” Science 312, 1780-1782 (2006). • [2] U. Leonhardt, ”Optical conformal mapping,” Science 312, 1777-1780 (2006). • [3] P. Knupp, and S.Steinberg,“Fundamentals of Grid Generation,” (CRC Press, Boca Raton, 1994). • [4] J. F. Thompson, B. K. Soni, and N. P. Weatherill, ”Handbook of Grid Generation,” (CRC Press, Boca Raton,1999). • [5] D. Schurig, et al. ”Metamaterial electromagnetic cloak at microwave frequencies,” Science 314, 977-980 (2006).

25. Reference • [6] J. Li, and J. B. Pendry, ”Hiding under the carpet: A new strategy for cloaking,” Phys. Rev. Lett. 101, 203901 (2008). • [7] R. Liu, C. Ji, J. J. Mock, J. Y. Chin, T. J. Cui, and D. R. Smith, ”Broadband ground-plane cloak,” Science 323, 366-369 (2009). • [8] J. Valentine, J. Li, T. Zentgraf, G. Bartal, and X. Zhang, ”An optical cloak made of dielectrics,” Nat. Mater. 8,568-571 (2009). • [9] L. H. Gabrielli, J. Cardenas, C. B. Poitras, and M. Lipson, ”Silicon nanostructure cloak operating at optical frequencies,” Nat. Photon., in press (2009). • [10] H.F. Ma, W.X. Jiang, X.M. Yang, X.Y. Zhou, and T. J. Cui“Caopact-size and Broadband Carpet Cloak and Free-space Cloak”,2009.