Lorenz-Mie Theory-Type Solutions for the Optical Properties of Spheroids with Small-to-Large Size Parameters and Aspect Ratios

There has been a long-term endeavor in the light-scattering research community to develop a Lorenz-Mie theory-type method for the solutions to light scattering by a spheroidal particle with a small-to-large size. Spheroid is an important nonspherical shape in modeling the optical properties of many realistic particles for many practical applications, including remote sensing of dust aerosol properties. For the first time, we develop a computationally feasible separation of variable method (SVM) in the spheroidal coordinates in conjunction with using the Wigner-d functions to compute optical properties of spheroids with small-to-large sizes compared to the wavelength of the incident light. In particular, the method is applicable to spheroids with size parameters up to 600 and is not restricted by particle aspect ratios. Therefore, the work reported here represents a breakthrough in solving the optical properties of a nonspherical particle in an analytical form.