Estimation of optical constants from multiple-scattered light using approximations for single particle scattering...

Area of Science:

• Optics
• Materials Science
• Computational Physics

Background:

• Optical constant determination from multiple-scattered light is computationally demanding.
• Calculating single particle characteristics (cross sections, anisotropy, phase function) is a major bottleneck.

Purpose of the Study:

• To investigate approximations for computing single particle characteristics.
• To significantly accelerate optical constant inversion calculations without sacrificing accuracy.

Main Methods:

• Evaluated approximations for absorption and scattering cross sections, anisotropy factor, and phase function.
• Used spherical polystyrene and poly(methyl methacrylate) particle suspensions.
• Compared exact Mie theory calculations with approximations like Henyey-Greenstein.

Main Results:

• The combination of exact Mie theory for cross sections/anisotropy and Henyey-Greenstein for the phase function provided optimal results.
• Approximation accuracy is sensitive to the phase function's behavior at small scattering angles.

Conclusions:

• Approximating the phase function using Henyey-Greenstein alongside exact Mie theory for other parameters significantly speeds up optical constant inversion.
• Minimizing phase function errors at small angles is crucial for accurate optical constant determination.