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A.A. Chabanov, Abe Pena ( UT-San Antonio ) Jing Wang, A.Z. Genack ( Queens College of CUNY)

Speckle Fluctuations and Correlation. A.A. Chabanov, Abe Pena ( UT-San Antonio ) Jing Wang, A.Z. Genack ( Queens College of CUNY). Speckles. Wave propagation in disordered media. wavelength. mean free path. Field. Intensity. Wave diffusion in a disordered medium. wavelength.

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A.A. Chabanov, Abe Pena ( UT-San Antonio ) Jing Wang, A.Z. Genack ( Queens College of CUNY)

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  1. Speckle Fluctuations and Correlation A.A. Chabanov, Abe Pena (UT-San Antonio) Jing Wang, A.Z. Genack (Queens College of CUNY)

  2. Speckles

  3. Wave propagation in disordered media wavelength mean free path Field Intensity

  4. Wave diffusion in a disordered medium wavelength mean free path Average intensity: Gaussian statistics: only the pairs of identical paths have the same phase and thus give a contribution to the average intensity

  5. Wave diffusion in a disordered medium Diffusion equation for the average intensity: (This equation would yield the Ohm’s law for a disordered conductor)

  6. Probability of return: wave particle A* A • transport reduction • nonlocal correlation • weak localization • non-Gaussian statistics Wave interference

  7. Transmission coefficients a b′ a′ b Transmitted intensity = speckle intensity Total transmission = brightness Transmittance = conductance

  8. Transmission coefficients i.e., Beenakker, RMP (1997)

  9. Statistics of tab and Tab AAC & Genack, PRA (2005) Kogan & Kaveh, PRB (1995)

  10. Alumina sample alumina sphere: d=0.9 cm n=3.14 f=0.068 copper tube: D=7.3 cm

  11. B A C Frequency (GHz) <Iab(t)> time (ns) Transmission in alumina samples σ= 5 MHz L=60 cm, 10,000 sample configurations A: ν=14.7-15.7 GHz, var(sab)=1.18, diffusive wave B: ν=9.95-10.15 GHz, var(sab)=6.18, localized wave C: t=740 ns, var[sab(t)]=20.1, strongly localized wave

  12. Gaussian statistics: Transmitted field distribution

  13. Characteristic and distribution functions of total transmission Nieuwenhuizen & vanRossen (1995) Stoytchev & Genack (1999)

  14. Factorizing of statistics of the field and intensity Fluctuations: Correlations:

  15. Correlation with polarization AAC, Hu & Genack (2004)

  16. Statistics of total transmission In localized regime (only one open channel):

  17. Statistics of transmission quantities in localized regime Pnini (2001)

  18. Correlation with wave polarization

  19. Intensity correlation of localized waves

  20. Intensity correlation of localized waves

  21. Conclusions • In a given random configuration, the statistics of transmitted field is Gaussian for both diffusive and localized waves; non-Gaussian mesoscopic field statistics arise in ensemble of configurations due to mesoscopic fluctuations of transmission • In localized regime, the transmitted intensity can be written as a product of three statistically independent variables; two of them have Rayleigh distribution • Future work: In diffusive regime (many channels): ?

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