Negative Index of Refraction

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Negative Index of Refraction

• Betsey Mathew

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Mathematically What is n?
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Permittivity

• Describes how affects the material
  electrically
• ? can be
• Positive (dielectric)
• Negative (metal)

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Permeability

• Describes how affects the material
  magnetically
• ? can be
• Positive (ferromagnet)
• Negative? (well look more at this later)

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Mathematically What makes a negative n?

• So if ? and ? are both negative then ?r and ?r
  are negative as well

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What is a NIM/LHM?

• NIM Negative Index of refraction Material
• Any material that has a n
• Must have e and µ
• LHM Left Handed Material

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Veselago

• Russian Physicist
• First theorized about NIMs in 1968
• Thought that NIMs would exhibit left-handed
  tendencies
• Thought that they would follow Snells law
• These theories couldnt be testedno µ materials
  existed

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Split-Ring Resonators

• Pendrys Cylinder
• Uses Faradays law to induce current
• Capacitance keeps current flowing
• Found Have and Bave

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Split-Ring Resonators
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Split-Ring Resonators
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Split-Ring Resonators
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Experiment 1 Design
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Experiment 1 Design
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Experiment 1 Results
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Experiment 2 Design
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Experiment 2 Results

• Snells law holds
• For ntlt0, ?tlt0

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Experiment 2 Conclusions
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Experiment 3 Design
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Experiment 3 Results

• We indeed see Snells law in action
• The numerical predictions match the datawe
  understand whats going on!

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Experiment 3 Results
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Experiment 3 Conclusions

• Snells law does indeed hold in NIMs
• The value of n follows predicted curves

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Overall Discoveries About LHMs Since 1999

• SRRs can be used to create µeff
• SRRs can have varying values of µeff depending
  on frequency
• When combined with wires, SRRs form LHMs
• These LHMs can be treated as a homogenous
  isotropic material
• Snells Law holds for these LHMs

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Possible Applications

• Pendry perfect lens
• Antennas
• Imaging with super-resolution
• Microwave devices
• Dispersion-compensating interconnects
• Radar

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Current Obstacles

• Resonance frequencies for µeff in SRRs are very
  high (GHz and THz)
• There are huge power losses that as yet cannot be
  overcome

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Sources

• Shelby, R. A., D. R. Smith, S. Schultz.
  Experimental Verification of a Negative Index of
  Refraction Science Vol. 292 April 2001
•  
• Parazzoli, C. G., R. B. Greegor, K. Li, B. E. C.
  Koltenbah, and M. Tanielian. Experimental
  Verification and Simulation of Negative Index of
  Refraction using Snells Law Physical Review
  Letters Vol. 90, No. 10. March 2003
• Smith, D. R., Willie J. Padilla, D. C. Vier, S.
  C. Nemat-Nasser, and S. Schultz. Composite
  Medium with Simultaneously Negative Permeability
  and Permittivity Physical Review Letters Vol.
  84, No. 18. May 2000
• Pendry, J. B., A. J. Holden, D. J. Robbins and W.
  J. Stewart. Magnetism from conductors and
  enhanced nonlinear phenomena IEEE Transactions
  on Microwave Theory and Techniques, Vol. 47, No.
  11. November 1999
• Hecht, Eugene. Optics, Fourth Ed. Addison Wesley,
  2002.
• Griffiths, David J. Introduction to
  Electrodynamics. Prentice Hall, 1999

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The End