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|Title: ||Multiple scattering of waves by dense random distributions of particles for applications in light scattering by noble metal nanoparticles and microwave scattering by terrestrial snow|
|Other Titles: ||Zhong jie zhi de duo chong san she ying yong yu gui jin shu na mi li zi de guang san she yu xue di de wei bo san she|
|Authors: ||Tse, Ka-ki (謝加琪)|
|Department: ||Department of Electronic Engineering|
|Degree: ||Doctor of Philosophy|
|Issue Date: ||2009|
|Publisher: ||City University of Hong Kong|
|Subjects: ||Multiple scattering (Physics)|
Light -- Scattering.
Precious metals -- Optical properties.
Nanoparticles -- Optical properties.
|Notes: ||CityU Call Number: QC173.4.M85 T75 2009|
1 v. (various pagings) : ill. (some col.) 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2009.
Includes bibliographical references.
|Abstract: ||In this dissertation, the multiple scattering of waves by dense random distribution
of particles is investigated. The Numerical Maxwell Model of three-dimensional
simulations (NMM3D) is applied to solve the multiple scattering numerically. The
positions of the particles are generated by the Monte Carlo method for both non-sticky
particles and sticky particles. The simulation results are useful for applications in
remote sensing related to terrestrial snow as well as nanotechnology.
In the studies of the light scattering by noble metal nanoparticles, we show the
scattering properties of such nanoparticles that exhibit plasmon resonance. We study
adhesive nanoparticles and also extinction and absorption as a function of
concentrations. Results indicate that the plasmon resonance can disappear for high
concentration of nanoparticles. The bistatic scattering properties described by the
phase matrix of the scattering of the nanoparticles is studied. A similar trend of
Rayleigh scattering is obtained with also a dominant forward scattering. Presented
results are based on Mie theory instead of the dipole approximation which is widely
used in the studies of scattering by nanoparticles. With enough number of particles
being included in the system, the results give a good estimation for scattering
properties of huge number of nanoparticles.
In the studies of microwave scattering by terrestrial snow, the results are
presented for the co-polarization and cross polarization scattering phase matrices and
the extinction coefficients of sticky particles. We consider concentrations of
particles up to 40% by volume. Results of dense media simulations depart from the
predictions based on classical theory of independent scattering which is applicable for very low concentrations. The simulation results (NMM3D) agree with those of the
quasicrystalline approximation (QCA) for concentration up to 20%. However, they
start to deviate from those of the QCA for higher concentrations as QCA
underestimates the extinction. Simulations results also predict strong cross
polarization in the phase matrix of densely packed spheres. This is the unique
feature of NMM3D that is neither predicted by classical independent scattering nor by QCA.|
|Online Catalog Link: ||http://lib.cityu.edu.hk/record=b2375055|
|Appears in Collections:||EE - Doctor of Philosophy |
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