scholarly journals Light Scattering by Particles with Arbitrary Shape in the Vicinity of the Backward Scattering Direction within Geometrical Optics Approximation

2020 ◽  
Vol 237 ◽  
pp. 08012
Author(s):  
Victor Shishko ◽  
Alexander Konoshonkin ◽  
Natalia Kustova ◽  
Anatoli Borovoi ◽  
Dmitry Timofeev
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Light Scattering ◽  
Arbitrary Shape ◽  
Specular Reflection ◽  
Scattering Problem ◽  
Geometrical Optics ◽  
Optical Characteristics ◽  
Ice Particles ◽  
Scattering Light

The work presents the solution for the light scattering problem by arbitrarily-shaped particles in the vicinity of the backward scattering direction. The solution was obtained within the framework of the geometrical optics approximation. The refractive index was equal to 1.3116. It was shown that the general contribution of scattering light for arbitrarily-shaped particles in the vicinity of the backscattering direction consists of the specular reflection of the particles and two types of non-specular optical beams. It is shown that the optical characteristics of the ice particles with arbitrary shapes correspond to experimental data.

Particle Identification Using Light Scattering

2009 ◽  
pp. 143-160
Author(s):  
M. C. Bartholomew-Biggs ◽  
Z. Ulanowski ◽  
S. Zakovic
Keyword(s):  
Experimental Data ◽  
Global Optimization ◽  
Light Scattering ◽  
Least Squares ◽  
Scattering Problem ◽  
Data Fitting ◽  
Particle Identification ◽  
Identification Procedure ◽  
Robust Identification ◽  
Actual Particle

We discuss some experience of solving an inverse light scattering problem for single, spherical, homogeneous particles using least squares global optimization. If there is significant noise in the data, the particle corresponding to the “best” solution may not correspond well to the “actual” particle. One way of overcoming this difficulty involves the use of peak positions in the experimental data as a means of distinguishing genuine from spurious solutions. We introduce two composite approaches which combine conventional data fitting with peak-matching and show that they lead to a more robust identification procedure.

scholarly journals Algorithm for Solving the Light Scattering Problem for Arbitrary Shaped Ice Particles with Absorption

2020 ◽  
Vol 237 ◽  
pp. 08004
Author(s):  
Timofeev D.N. ◽  
Konoshonkin A.V. ◽  
Kustova N.V. ◽  
Borovoi A.G.
Keyword(s):  
Light Scattering ◽  
Scattering Problem ◽  
Scattering Matrix ◽  
Influence Effect ◽  
Ice Particles ◽  
Scattering Matrices ◽  
Research Show

The work presents the estimation of the absorption influence effect on the light scattering problem for atmospheric ice particles. The calculation of light scattering matrices was performed for two types of particles: the solid hexagonal columns and the arbitrary shaped particles. The range of the size for both types of particles varies from 10 μm to 1000 μm. The results of the research show an insignificant decrease of the value of the M11 element of the light scattering matrix for small-sized particles for all chosen wavelengths (0.355 μm, 0.532 μm, 1.064 μm и 1.6 μm), and a significant decrease for big-sized particles for a 1.6 μm wavelength.

scholarly journals Calculations of Light Scattering Matrix of Dust Aerosols for Problems of Lidar Remote Sensing

2020 ◽  
Vol 237 ◽  
pp. 08008
Author(s):  
Natalia Kustova ◽  
Alexander Konoshonkin ◽  
Anatoli Borovoi ◽  
Zhenzhu Wang ◽  
Dong Liu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Remote Sensing ◽  
Refractive Index ◽  
Light Scattering ◽  
Scattering Matrix ◽  
Dust Particles ◽  
Exact Methods ◽  
Particle Orientations ◽  
Crucial Parameter ◽  
Good Agreement

The light scattering matrix is calculated for large dust particles with irregular shape and refractive index of 1.3116+i0.0. The scattering matrix in the backward direction needed for lidar studies is separately discussed. In this case, the obtained results for the lidar and depolarization ratios are in good agreement with experimental data. It is shown that for randomly oriented particles the number of particle orientations needed for numerical calculations by exact methods like DDA becomes a crucial parameter. In particular, for particles with size parameters larger than 40 the number of orientations should be more than 1000.

Stress Whitening in Polypropylene. I. Light Scattering Theory and Model Experiments

1995 ◽  
Vol 60 (11) ◽  
pp. 1875-1887 ◽  
Author(s):  
Jaroslav Holoubek ◽  
Miroslav Raab
Keyword(s):  
Refractive Index ◽  
Light Scattering ◽  
Incident Light ◽  
Polymeric Materials ◽  
Wavelength Dependence ◽  
Theoretical Background ◽  
Surrounding Matrix ◽  
Embedded Particles ◽  
The One ◽  
Stress Whitening

Theoretical background for an optical method is presented which makes it possible to distinguish unambiguously between voids and particles as light scattering sites in polymeric materials. Typical dependences of turbidity as a function of diameter of scattering elements, their volume fractions and also turbidity curves as a function of the wavelength of the incident light were calculated, based both on the Lorenz-Mie theory and the fluctuation theory. Such dependences calculated for polypropylene-containing voids on the one hand and particles, differing only slightly from the surrounding matrix in their refractive index, on the other hand, are markedly different. The most significant results are: (i) Turbidity is at least by two orders of magnitude larger for voids in comparison to embedded particles of ethylene-propylene (EPDM) rubber of the same size, concentration and at the same wavelength. (ii) The wavelength dependence of turbidity for EPDM particles and the inherent refractive index fluctuations in the polypropylene matrix is much steeper as compared to voids for all considered diameters (0.1-10 μm). Thus, the nature of stress whitening in complex polymeric materials can be determined from turbidity measurements.

Investigations of the Optical Properties of LaNi5 and LaNi4.5Sn0.5

2013 ◽  
Vol 321-324 ◽  
pp. 495-498 ◽  
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Optical Properties ◽  
Density Functional ◽  
Low Frequency ◽  
Potential Method ◽  
Frequency Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The reflectivity, loss function, refractive index, extinction coefficient and dielectric function of the LaNi5and LaNi4.5Sn0.5intermetallic compounds are investigated through the plane-wave pseudo-potential method based on the density functional theory. The effects of Sn impurity are discussed and some interesting features are found in the low frequency region. Some important optical properties such as static dielectric constant and static refractive index are obtained. The equation [n (0)]2=ε1(0)is satisfied according to our calculation, which indicates that our results are correct and reasonable. Nevertheless, the calculated results need to be testified in the future due to the lack of experimental data.

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