Internal and near-surface electromagnetic fields for a spheroidal particle with arbitrary illumination

Area of Science:

• Electromagnetics
• Computational physics
• Optical properties of materials

Background:

• Understanding electromagnetic fields near particles is crucial for applications like light scattering and sensing.
• Spheroidal particles are common in nature and technology, but their electromagnetic behavior is complex.
• Existing methods may not fully capture the intricate field distributions for arbitrary incident fields.

Purpose of the Study:

• To develop a theoretical framework for calculating internal and near-surface electromagnetic fields of homogeneous spheroidal particles.
• To investigate the influence of particle geometry (prolate and oblate) and incident field characteristics on field distributions.
• To provide a versatile computational tool for analyzing light-matter interactions with spheroidal particles.

Main Methods:

• A separation-of-variables solution in spheroidal coordinates was employed.
• The theoretical procedure was applied to homogeneous particles with both prolate and oblate geometries.
• Simulations considered various particle sizes, axis ratios, and incident field types (plane-wave, Gaussian beam).

Main Results:

• The study successfully determined internal and near-surface electromagnetic field distributions.
• Results demonstrate the significant impact of particle size, axis ratio, and incident field orientation.
• Differences in field patterns were observed for prolate versus oblate shapes and different incident beam types.

Conclusions:

• The developed theoretical procedure provides accurate electromagnetic field calculations for spheroidal particles.
• Particle morphology and incident wave properties critically govern near-field electromagnetic behavior.
• This work offers valuable insights for manipulating and understanding light interactions with non-spherical particles.