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Anderson Localization of Electromagnetic Waves

Sheikhan Soudani, Amene | 2010

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 40511 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Rahimi Tabar, Mohammad Reza
  7. Abstract:
  8. The electrons scatter by the impurities during propagation through the media and become localized by increasing the impurities. So the metal insulator transition occurs. This phenomenon was first proposed by W. Anderson and is known as Anderson Localization. In this thesis the Anderson localization of electromagnetic waves is investigated. The disordered media with random dielectric constant is studied by considering Maxwell’s equations. There are different numerical methods to study this phenomenon such as transfer matrix method and level statistics we have used in this thesis. In three dimension, different scaling behavior shows the phase transition from localized states to extended states and the phase space is plotted for different frequencies and different intensity of disorder. The level statistics of electromagnetic model indicates its universality class which is the class of Gaussian Orthogonal Matrices. The critical exponent in three dimension is similar to the Anderson model. Also we consider the random dielectric constant with short range correlation in medium known as random dimer. We investigated this model with transfer matrix method and dynamical method to show that there are specific modes can propagate through this quasi one dimensional random media. These modes depend on the dielectric constant and are calculated analytically which are the same as numerical results. Similarly in one dimension with random dielectric constant we introduce the dynamical method to calculate the localization length and the results are in good agreement with the results of transfer matrix method. The wave packet with wide range of frequencies is sent to the medium and the localization length can be calculated by the decay of intensity of transmitted light in different distances from the source. Due to the frequency dependence of localization length, the spectral density of incident wave packet has a red shift by propagation through the medium. Finally we apply an imaging method for electromagnetic waves to detect the single optical scatterers and also the coherent backscattering of light from random media is investigated
  9. Keywords:
  10. Anderson Localization ; Transfer Matrix Method ; Electromagnetic Wave ; Energy Level Statistics ; Random Dimer Model ; Red Shift ; Coherent Back Scattering

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