Validation of the born approximation in 2-D weakly-scattering biological random media using the FDTD method

2009 ◽  
Author(s):  
Ilker R. Capoglu ◽  
Vadim Backman
Keyword(s):  
Born Approximation ◽  
Random Media ◽  
Fdtd Method

scholarly journals Spectral Intensity Variation by the Correlation Function of Refractive Index Fluctuations of the Liquid Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
Nageshwar Singh
Keyword(s):  
Refractive Index ◽  
Correlation Function ◽  
Liquid Medium ◽  
Born Approximation ◽  
Random Media ◽  
Intensity Variation ◽  
Spectral Intensity ◽  
Far Field ◽  
Macroscopic Theory ◽  
Spatial Correlation Function

It is proposed that a macroscopic theory of propagation and scattering of light through random media can be functional for the dye liquid flowing media in the microscopic levels too, with modest approximations. Maxwell’s equation for a random refractive index medium is approximated and solved for the electric field. An analytical expression for the spectral intensity of the field scattered by the refractive index fluctuations inside a medium has been derived which was valid within the first Born approximation. Far field spectral intensity variation of the radiation propagating through the liquid medium is a consequence of variation in correlation function of the refractive index inhomogeneities. The strength of radiation scattered in a particular direction depends on the spatial correlation function of the refractive index fluctuations of the medium. An attempt is made to explain some of the experimentally observed spectral intensity variations, particularly dye emission propagation through liquid flowing medium, in the presence of thermal and flow field.

Accuracy of the Born approximation in calculating the scattering coefficient of biological continuous random media

2009 ◽  
Vol 34 (17) ◽  
pp. 2679 ◽  
Author(s):  
İlker R. Çapoğlu ◽  
Jeremy D. Rogers ◽  
Allen Taflove ◽  
Vadim Backman
Keyword(s):  
Born Approximation ◽  
Random Media ◽  
Scattering Coefficient

Nonscalar elastic light scattering from continuous random media in the Born approximation

2009 ◽  
Vol 34 (12) ◽  
pp. 1891 ◽  
Author(s):  
Jeremy D. Rogers ◽  
İlker R. Çapoğlu ◽  
Vadim Backman
Keyword(s):  
Light Scattering ◽  
Born Approximation ◽  
Random Media ◽  
Elastic Light Scattering

Stochastic LOD-FDTD method for two-dimensional electromagnetic uncertainty problems

2017 ◽  
Vol 36 (5) ◽  
pp. 1442-1456 ◽  
Author(s):  
Christos Salis ◽  
Nikolaos Kantartzis ◽  
Theodoros Zygiridis
Keyword(s):  
Electromagnetic Fields ◽  
Random Media ◽  
Fdtd Method ◽  
Correlation Coefficients ◽  
Unconditional Stability ◽  
Delta Method ◽  
Two Dimensional ◽  
Deterministic Models ◽  
Content Type ◽  
Material Uncertainties

Purpose Random media uncertainties exhibit a significant impact on the properties of electromagnetic fields that usually deterministic models tend to neglect. As a result, these models fail to quantify the variation in the calculated electromagnetic fields, leading to inaccurate outcomes. This paper aims to introduce an unconditionally stable finite-difference time-domain (FDTD) method for assessing two-dimensional random media uncertainties in one simulation. Design/methodology/approach The proposed technique is an extension of the stochastic FDTD (S-FDTD) scheme, which approximates the variance of a given field component using the Delta method. Specifically in this paper, the Delta method is applied to the locally one-dimensional (LOD) FDTD scheme (hence named S-LOD-FDTD), to achieve unconditional stability. The validity of this algorithm is tested by solving two-dimensional random media problems and comparing the results with other methods, such as the Monte-Carlo (MC) and the S-FDTD techniques. Findings This paper provides numerical results that prove the unconditional stability of the S-LOD-FDTD technique. Also, the comparison with the MC and the S-FDTD methods shows that reliable outcomes can be extracted even with larger time steps, thus making this technique more efficient than the other two aforementioned schemes. Research limitations/implications The S-LOD-FDTD method requires the proper quantification of various correlation coefficients between the calculated fields and the electrical parameters, to achieve reliable results. This cannot be known beforehand and the only known way to calculate them is to run a fraction of MC simulations. Originality/value This paper introduces a new unconditional stable technique for measuring material uncertainties in one realization.

scholarly journals Structural length-scale sensitivities of reflectance measurements in continuous random media under the Born approximation

2012 ◽  
Vol 37 (24) ◽  
pp. 5220 ◽  
Author(s):  
Andrew J. Radosevich ◽  
Ji Yi ◽  
Jeremy D. Rogers ◽  
Vadim Backman
Keyword(s):  
Born Approximation ◽  
Random Media ◽  
Length Scale ◽  
Reflectance Measurements ◽  
Structural Length
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