27-10-2012, 11:48 AM
Finite-Difference Time Domain Solution of Light Scattering and Absorption by Particles in an Absorbing Medium
ABSTRACT
The three-dimensional (3-D) finite-difference time-domain (FDTD) technique has been extended to simulate light
scattering and absorption by nonspherical particles embedded in an absorbing dielectric medium. A uniaxial perfectly matched
layer (UPML) absorbing boundary condition is used to truncate the computational domain. When computing the
single-scattering properties of a particle in an absorbing dielectric medium, we derive the single-scattering properties including
scattering phase functions, extinction, and absorption efficiencies using a volume integration of the internal field. A Mie
solution for light scattering and absorption by spherical particles in an absorbing medium is used to examine the accuracy of
the 3-D UPML FDTD code. It is found that the errors in the extinction and absorption efficiencies from the 3-D UPML FDTD
are less than similar to 2%. The errors in the scattering phase functions are typically less than similar to 5%. The errors in the
asymmetry factors are less than similar to 0.l%. For light scattering by particles in free space, the accuracy of the 3-D UPML
FDTD scheme is similar to a previous model.