Light scattering patterns of pendant drops. II. Simulation method and mechanism analysis

The study of light scattering by particles promotes our understanding of natural phenomena and drives advancements in optical technologies. However, the existing methods and models face challenges in addressing the light scattering by nonspherical particles of size much larger than light wavelength, such as pendant drops found in nature (e.g., on leaves) or laboratories (e.g., in capillary tubes). The experimental results presented in the companion paper revealed that pendant drops exhibit unique and complex light scattering patterns distinct from those of spherical drops. Understanding how pendant drops scatter light remains an unresolved scientific challenge. In this paper, the simulation for the light scattering patterns of real pendant drops is achieved by extending the vectorial complex ray model we developed earlier for three-dimensional scattering. The simulated results are carefully examined and agree well with the experimental findings. In addition, the mechanisms underlying these complex light scattering patterns are also investigated, offering novel insights into how scattering pattern evolves with drop-shape deformation. Beyond the theoretical importance, this work permits interrelation of the light scattering patterns with the drop's shape, size, and refractive index/temperature, thus holding practical potential, particularly in developing relevant optical measurement techniques.