Retrieving the Aerosol Complex Refractive Index using PyMieScatt: A Mie Computational Package with Visualization Capabilities

TL;DR

PyMieScatt is an open-source Python package that enables the retrieval of the complex refractive index of particles from optical measurements, supporting various particle types and visualization of solutions.

Contribution

It introduces a comprehensive Python tool for solving the inverse Mie problem, including solution regions and visualization, which was previously difficult to perform efficiently.

Findings

Provides a method for inferring complex refractive index from optical data

Supports analysis of homogeneous and coated spheres, and ensembles with size distributions

Includes visualization tools for solution regions and error bounds

Abstract

The complex refractive index m=n+ik of a particle is an intrinsic property which cannot be directly measured, it must be inferred from its extrinsic properties such as the scattering and absorption cross-sections. Bohren and Huffman called this approach describing the dragon from its tracks, since the inversion of Lorenz-Mie theory equations is intractable without the use of computers. This article describes PyMieScatt, an open-source module for Python that contains functionality for solving the inverse problem for complex m using extensive optical and physical properties as input, and calculating regions where valid solutions may exist within the error bounds of laboratory measurements. Additionally, the module has comprehensive capabilities for studying homogeneous and coated single spheres, as well as ensembles of homogeneous spheres with user-defined size distributions, making it a complete tool for studying the optical behavior of spherical particles.