Equiphase-sphere approximation for analysis of light scattering by arbitrarily shaped nonspherical particles

Area of Science:

• Optics
• Computational Physics
• Materials Science

Background:

• Light scattering analysis is crucial for understanding particle properties.
• Existing methods for irregularly shaped particles can be computationally intensive.
• The equiphase sphere (EPS) concept offers a potential simplification.

Purpose of the Study:

• To extend the equiphase sphere (EPS) concept for analyzing light-scattering properties of arbitrarily shaped particles.
• To develop a simplified method for calculating total scattering cross-section (TSCS) spectra.
• To establish validity conditions for the EPS approximation.

Main Methods:

• Utilized the Wentzel-Kramers-Brillouin (WKB) technique.
• Performed numerical studies using the finite-difference time-domain (FDTD) method.
• Approximated irregularly shaped particles with equivalent equiphase ellipsoids.

Main Results:

• Demonstrated that a wide range of irregularly shaped particles can be approximated by their equivalent equiphase ellipsoids.
• Showed that the EPS approximation provides a simple expression for calculating total scattering cross-section (TSCS) spectra.
• Identified that the accuracy of the EPS approximation depends on surface perturbation magnitude and scale.

Conclusions:

• The EPS approximation offers an efficient method for calculating TSCS spectra of irregularly shaped particles.
• Derived validity conditions for the EPS approximation enhance its practical applicability.
• This approach facilitates the study of light-scattering phenomena for complex particle geometries.