复旦【部队提案】 隐身材料0523版)

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复旦【部队提案】 隐身材料0523版)

  1. 1. Terahertz Invisible Cloaking MINGYU.SHENG
  2. 2. Outline <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>
  3. 3. <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>Outline
  4. 4. Three kinds of “invisible cloaking” Invisible cloaking based on Transform Optics Theory Invisible cloaking based on plasma theory Invisible cloaking applied in F117 jet
  5. 5. <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>摘 要
  6. 6. What is THZ and its applications Photons Electrons THz Gap
  7. 7. What is THZ and its applications Collision Avoidance Personnel insertion / extraction Composite imaging Biomedical imaging Space exploration Personnel screening
  8. 8. <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>摘 要
  9. 9. Terahertz Invisible Cloaking
  10. 10. <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>摘 要
  11. 11. Theory of Transformation Optics John Pendry Imperial College David Smith Duke University A Chiral Route to Negative Refraction Science 306 1353-5 (2004) JB Pendry Controlling Electromagnetic Fields Science 312 1780-2 (2006). JB Pendry , D Schurig , and DR Smith
  12. 12. <ul><li>How to bend Light </li></ul><ul><li>A Mirage – the refractive index varies continuously near the road surface </li></ul>Theory of Transformation Optics
  13. 13. <ul><li>General Relativity: gravity changes geometry. </li></ul><ul><li>Therefore gravity should bend light </li></ul>Theory of Transformation Optics
  14. 14. <ul><li>Electromagnetic Invisibility – the Ray Trajectories </li></ul>Theory of Transformation Optics
  15. 15. Designing Space for Light with Transformation Optics Spatial profile of  &  tensors determines the distortion of coordinate Seeking for profile of  &  to make wave avoid particular region in space — invisible cloaking Straight field line in Cartesian coordinate Distorted field line in distorted coordinate
  16. 16. <ul><li>U. Leonhardt, “Optical conformal mapping”, Science, 312, 1777, June, 2006. </li></ul><ul><li>U. Leonhardt and T. G. Philbin, arXiv:0805.4778v2, 2008 </li></ul><ul><li>J. B. Pendry, D. Schurig, and D. R. Smith, “Controlling Electromagnetic Fields”, Science, 312, 1780, June, 2006. </li></ul>Coordinate Transformation Cartesian coordinate distorted coordinate
  17. 17. Form-invariance of Maxwell’s equations
  18. 18. <ul><li>U. Leonhardt, “Optical conformal mapping”, Science, 312, 1777, June, 2006. </li></ul><ul><li>J. B. Pendry, D. Schurig, and D. R. Smith, “Controlling Electromagnetic Fields”, Science, 312, 1780, June, 2006. </li></ul>Coordinate transformations are equivalent to the changes of  and  Original Cartesian coordinate ( x, y, z ) New coordinate ( q 1 , q 2 , q 3 ) The Maxwell equations can take the invariant form as with Coordinate Transformation Jacobian Transformation matrix
  19. 19. <ul><li>At the exterior boundary of the cloak: no reflection </li></ul><ul><li>At the inner boundary: no reflection </li></ul><ul><li>No field can penetrate into the cloaked region. </li></ul>Arbitrarily –shaped invisibility cloaks are perfectly invisible! General cross-section: Ref: Z. Ruan, M. Yan, C. W. Neff, and M. Qiu, “Ideal cylindrical cloak:  Perfect but sensitive to tiny perturbations”, Phys. Rev. Lett.  Vol. 99, No. 11, 113903 (2007). Line transformed cloak Point transformed cloak Point and line cloaking
  20. 20.  (x,y,z),  (x,y,z) Original medium in the (x, y, z) space Transformed medium again in the (x, y, z) space circle-plane cloaking Coordinate transformation
  21. 21. x y z Arbitrary Shape plane cloaking
  22. 22. x y z Transformed medium/field
  23. 23.   ,   approach infinity at r=a! a b Phys. Rev. Lett. 99, 113903, 2007 Material requirement is a problem for line transformed cloak: infinity Cylindrical Cloak Ideal cylindrical cloak material parameters
  24. 24. <ul><li>Material parameters(  ,  ) approach infinity at boundary. </li></ul><ul><li>Materials are Lossless. </li></ul><ul><li>Material parameters(  ,  ) are very complex, such as anisotropic, inhomogeneous and so on. </li></ul>Limitations of Transformation Optics
  25. 25. <ul><li>Background: Three kinds of invisible cloaking </li></ul><ul><li>What is THZ and its applications </li></ul><ul><li>Terahertz Invisible Cloaking </li></ul><ul><li>Theory of Transformation Optics </li></ul><ul><li>Research plan </li></ul>摘 要
  26. 26. <ul><li>Simplify the material parameters(  ,  ) to realize the material </li></ul><ul><li>Realize the cylindrical cloak in Terahertz frequency range </li></ul>Research plan
  27. 27. The material parameters are simplified as Principle: Simplified cylindrical cloak in microwave
  28. 28. Min Yan, Zhichao Ruan, and Min Qiu, “Scattering characteristics of simplified cylindrical invisibility cloaks,” Opt. Express. 15, 17772, 2007. Principle: Black: ideal Green : simplified Red : improved Improving simplified cylindrical cloak  r    z
  29. 29. Linear simplified-cloak 1 Improved linear simplified-cloak (current work) Quadratic simplified-cloak 2 [1] D. Schurig, 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 314, 977–980 (2006). Simplified cloaks
  30. 30. Employ Metamaterial: Some typical microstructures
  31. 31. Coupled split-ring resonators magnetic-dipole moments are electric-dipole moments are 2R d
  32. 32. How to map  、  ?
  33. 33. To be considered: A set of microstructures
  34. 34. Thank you

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