Statistics of microwave radiation in the approach to localization.
Item
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Title
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Statistics of microwave radiation in the approach to localization.
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Identifier
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AAI9830766
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identifier
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9830766
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Creator
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Stoytchev, Marin.
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Contributor
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Adviser: Azriel Genack
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Date
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1998
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Condensed Matter | Physics, Optics
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Abstract
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We study the statistics of intensity and total transmission in mesoscopic systems in the approach to localization. The localization threshold is reached in measurements of microwave radiation transmitted through long waveguides with volume disorder. This is the realization using classical waves of the Thouless idea of localization of electrons in long wires. We find that, near the localization length, the probability distributions of intensity and total transmission deviate significantly from negative exponential statistics and from a normal distribution, respectively. For large values of these quantities, the corresponding distributions decay instead as a negative stretched exponential to the power 1/2 and as a simple negative exponential. We confirm experimentally the relationships between the moments of intensity and total transmission and their full distributions derived from RMT calculations for samples with quasi-1D geometry. These relations unify the statistical description of local and spatially averaged transmittance quantities. The results of these measurements show that the distributions of intensity and total transmission are not significantly affected even by the presence of strong absorption. The presence of absorption only postpones somewhat the approach to localization, but does not destroy localization. We find that the variances of intensity and total transmission are directly related to the degree of nonlocal intensity correlation and serve as a reliable with frequency shift of the total transmission. These functions are dominated by the long- and infinite-range correlation terms of the intensity correlation function and allow us to experimentally determine the frequency dependence of the infinite-range correlation term for the first time. In a proof of principle experiment of microwave transmission in a 3D periodic metal wire network possessing a photonic band gap, we demonstrate that, by creating an ensemble of random scatterer configurations within the "photonic crystal", it is also possible to investigate the statistics of the localization transition.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
