Internal dipole radiation as a tool for particle identification

Area of Science:

• Computational physics
• Electromagnetism
• Optical properties of materials

Background:

• Calculating internal dipole radiation is crucial for understanding light-matter interactions.
• Particles with complex morphologies pose challenges for traditional analytical methods.

Purpose of the Study:

• To investigate the discrete-dipole approximation (DDA) for calculating internal dipole radiation of arbitrarily shaped particles.
• To validate DDA accuracy by comparing it with analytical solutions and other numerical methods.

Main Methods:

• The discrete-dipole approximation (DDA) was employed to model internal dipole radiation.
• DDA results were compared against analytical solutions for spherical particles.
• DDA calculations for nonspherical particles were validated using the finite-difference time-domain (FDTD) method.

Main Results:

• DDA shows high accuracy for spherical particles when refractive index m < 2 and mkd < 0.5.
• Excellent agreement was observed between DDA and FDTD methods for nonspherical particles.
• Simulated sporelike particles demonstrated that DDA captures detailed radiation patterns.

Conclusions:

• The DDA method is a reliable numerical approach for internal dipole radiation calculations across diverse particle morphologies.
• Internal dipole radiation patterns derived from DDA provide significant insights into particle characteristics.
• DDA offers a versatile tool for studying light scattering and optical properties of complex microstructures.