Coherent Backscattering from Multiple Scattering Systems - KOPS ...

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6 Summary D = 13300 m2 /s. This agrees pretty well with results of measurements with the old setup and with the results of the wide angle experiments, which yield correct results if the diffusion coefficient obtained with the small angle setup is used for the evaluation. With these findings the reliability of the results of the small angle setup is confirmed. Another application for the small angle setup was to determine the transport mean free path of fluidized beds. As the scattering particles in these experiments are rather large and have a regularly spherical shape, the intensity distribution of the backscattered light is superimposed by the ring structure of the single scattering on the Mie particles. This structure can however be calculated theoretically and adapted to the measured curves, so that the backscattering cone can be extracted from the data. In first measurements the width of the backscattering cone led to a transport mean free path that was significantly shorter than the particle diameter of the scatterers. This is in strong contrast to the results of similar experiments, which are reported to be of the order of several particle diameters. The reason for this is still under discussion; however, the basic procedure for the evaluation of the backscattering data of fluidized beds was tested successfully. For future experiments, the combination of the two revised backscattering setups offers the unique possibility to measure kl ∗ over more than three decades, from samples at the transition to Anderson localization at kl ∗ ≈ 1 to weakly scattering samples with extremely narrow backscattering cones. Possible applications range from experiments on new, custom designed particles with small kl ∗ to measurements on foams or biological tissue. Some of these experiments are already planned for the near future, and will hopefully provide a step further towards fully understanding multiple scattering. 70
Bibliography [1] http://www.schneiderkreuznach.com/industrial filters/polarization filters.htms, 17.02.2010. [2] Matlab. The MathWorks Inc., 2007. [3] MiePlot. philip@philiplaven.com, 2008. [4] http://www.lenntech.com/teflon.htm, 2.11.2009. [5] C. M. Aegerter, M. Störzer, W. Bührer, S. Fiebig, and G. Maret, Experimental signatures of Anderson localization of light in three dimensions, Journal of Modern Optics, 54 (2007), p. 2667. [6] C. M. Aegerter, M. Störzer, S. Fiebig, W. Bührer, and G. Maret, Observation of Anderson localization of light in three dimensions, Journal of the Optical Society of America A, 24 (2007), p. A23. [7] C. M. Aegerter, M. Störzer, and G. Maret, Experimental determination of critical exponents in Anderson localisation of light, Europhysics Letters, 75 (2006), p. 562. [8] E. Akkermans and G. Montambaux, Coherent effects in the multiple scattering of light in random media, in Wave Scattering in Complex Media: From Theory to Applications, B. van Tiggelen and S. Skipetrov, eds., Kluwer Academic Publishers, 2003. [9] , Memo on cbs and conservation of energy. Private communication, May 2007. [10] , Mesoscopic Physics of Electrons and Photons, Cambridge University Press, 2007. ISBN 978-0-521-85512-9. [11] E. Akkermans, P. E. Wolf, and R. Maynard, Coherent backscattering of light by disordered media: Analysis of the peak line shape, Physical Review Letters, 56 (1986), p. 1471. [12] E. Akkermans, P. E. Wolf, R. Maynard, and G. Maret, Theoretical study of the coherent backscattering of light by disordered media, Journal de Physique France, 49 (1988), p. 77. [13] P. W. Anderson, Absence of diffusion in certain random lattices, Physical Review, 109 (1958), p. 1492. [14] , The question of classical localization - a theory of white paint, Philosophical Magazine B, 52 (1985), p. 505. [15] G. Bayer and T. Niederdränk, Weak localization of acoustic waves in strongly scattering media, Physical Review Letters, 70 (1993), p. 3884. [16] C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles, Wiley-Interscience, 1998. ISBN 0-471-29340-7.
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Dissertation Coherent Backscatterin
Page 3 and 4:
Ein kurzer Überblick Streuung ist
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Ein kurzer Überblick portweglänge
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Contents Ein kurzer Überblick i Da
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1 Introduction There have been many
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2 Theory In scattering theory, the
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2.2 Single scattering - Mie theory
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2.2 Single scattering - Mie theory
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2.3 Random walk and diffusion scatt
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2.3 Random walk and diffusion of pr
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2.4 The influence of boundaries Fig
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2.5 Photon flux from a surface The
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2.6 On polarization and interferenc
Page 27 and 28: 2.6 On polarization and interferenc
Page 29 and 30: 2.7 The theory of coherent backscat
Page 31 and 32: 2.7 The theory of coherent backscat
Page 33 and 34: 3 Setups 3.1 Laser System The key p
Page 35 and 36: 3.2 Wide Angle Setup 1 .0 0 .8 h e
Page 37 and 38: 3.3 Small Angle Setup 1 0.998 0.996
Page 39 and 40: 3.3 Small Angle Setup Figure 3.6: T
Page 41 and 42: 3.4 Time Of Flight Setup Figure 3.8
Page 43 and 44: 4 Samples 4.1 Sample characterizati
Page 45 and 46: 4.1 Sample characterization techniq
Page 47 and 48: 4.2 The samples sample particle siz
Page 49 and 50: 4.2 The samples Figure 4.5: Fluidiz
Page 51 and 52: 5 Experiments 5.1 Conservation of e
Page 53 and 54: 5.1 Conservation of energy in coher
Page 65 and 66: 5.2 The coherent backscattering con
Page 77: 6 Summary The focus of the work pre
Page 81 and 82: Bibliography [34] E. Larose, L. Mar
Page 83 and 84: Figures and Tables Figures Backscat
Page 85 and 86: Figures and Tables Tables 4.1 Collo
Page 87 and 88: MATLAB codes Angular intensity dist
Page 89 and 90: Evaluation of the wide angle data E
Page 91 and 92: Evaluation of the wide angle data %
Page 93 and 94: Evaluation of the wide angle data f
Page 95 and 96: Evaluation of the small angle data
Page 97 and 98: Evaluation of the small angle data
Page 99: Evaluation of the small angle data
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