The first part of this study is focused on numerical studies of light scattering
from a single microscopic particle using the Discrete Dipole Approximation (DDA)
method. The conventional DDA formalism is generalized to two cases: (a) inelastic
light scattering from a dielectric particle and (b) light scattering from a particle with
magnetic permeability u /= 1. The first generalization is applied to simulations of
Raman scattering from bioaerosol particles, and the second generalization is applied
to confi rmation of irregular invisibility cloaks made from metamaterials.
In the second part, radiative transfer in a coupled atmosphere-ocean system is
solved to study the asymptotic nature of the polarized light in deep oceans. The rate
at which the radiance and the polarization approach their asymptotic forms in an
ideal homogeneous water body are studied. Effects of the single scattering albedo
and the volume scattering function are studied. A more realistic water body with
vertical pro files for oceanic optical properties determined by a Case 1 water model
is then assumed to study the e ffects of wavelength, Raman scattering, and surface
waves.
Simulated Raman scattering patterns computed from the generalized DDA formalism
are found to be sensitive to the distribution of Raman active molecules in the
host particle. Therefore one can infer how the Raman active molecules are distributed from a measured Raman scattering pattern. Material properties of invisibility cloaks
with a few irregular geometries are given, and field distributions in the vicinity of
the cloaked particles computed from the generalized DDA formalism con rm that the
designated material properties lead to invisibility. The radiative transfer model calculation
in deep oceans suggest that the underwater radiance approaches its asymptotic
form more quickly than the polarization does. Therefore, a vector radiative transfer
solution is necessary for asymptotic light field studies. For a typical homogeneous
water body whose scattering property is characterized by the Petzold phase function,
a single scattering albedo of w0 > 0:8 is required in order that the asymptotic regime
can be reached before there are too few photons to be detected.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2008-08-46 |
| Date | 16 January 2010 |
| Creators | You, Yu |
| Contributors | Kattawar, George W., Yang, Ping |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation |
| Format | application/pdf |
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