miepython

Mie scattering calculations in pure Python

miepython provides a validated and efficient implementation of Mie scattering for spherical particles. It reproduces established reference results (including Wiscombe's MIEV0) and is designed for scientific, educational, and computational research applications in optics.

The library implements the full Mie solution, including:

• extinction, scattering, and absorption efficiencies
• asymmetry parameter (scattering anisotropy)
• angle-resolved scattering intensities
• Mie expansion coefficients
• complex amplitude functions and Mueller matrices

The implementation is numerically stable for a wide range of size parameters and refractive indices, including lossy materials and high-index contrasts.

Immediate Use in the Browser

The entire package can be used immediately in a browser — without installation — using the JupyterLite interface:

This environment runs entirely client-side (Pyodide), and supports:

• interactive notebooks
• real-time plotting
• full access to miepython functions
• reproducible experiments (downloadable notebooks)

This makes it ideal for teaching, demonstrations, or quick exploratory calculations.

Installation

Install with pip:

pip install miepython

Or via conda:

conda install -c conda-forge miepython

Quick Start

A typical calculation is straightforward:

import miepython as mie

m = 1.5 - 0.1j     # refractive index
d = 100            # diameter (nm)
lambda0 = 314.15   # wavelength (nm)

qext, qsca, qback, g = mie.efficiencies(m, d, lambda0)

Documentation and Examples

The full documentation is available as:

Interactive documentation (JupyterLite):

Static Jupyter notebooks on ReadTheDocs:

Among other things the documentation discusses:

• Mathematical formulation of Mie theory https://miepython.readthedocs.io/en/latest/01_theory.html
• Normalization conventions and units https://miepython.readthedocs.io/en/latest/02_normalization.html
• Numerical stability considerations https://miepython.readthedocs.io/en/latest/03_stability.html
• Validation against MIEV0 and other reference implementations https://miepython.readthedocs.io/en/latest/04_validation.html
• Guidelines for parameter choices and truncation order https://miepython.readthedocs.io/en/latest/05_truncation.html
• Physical interpretation, resonances, and comparison plots https://miepython.readthedocs.io/en/latest/06_examples.html

Representative results simple examples:

https://github.com/scottprahl/miepython/tree/main/miepython/examples

Performance and Acceleration

miepython supports optional Numba JIT compilation:

import os
os.environ["MIEPYTHON_USE_JIT"] = "1"  # must be set before import
import miepython

This can provide 10–50× speedups for large parameter sweeps or ensemble calculations.

Benchmark example (100,000 particles):

Version	Time	Speedup
Pure Python	4.00 s	1×
JIT Enabled	0.15 s	27×

Citation

If miepython contributes to your research, please cite the Zenodo archive:

DOI: 10.5281/zenodo.7949263

BibTeX:

@software{prahl_miepython_2025,
  author  = {Prahl, Scott},
  title   = {{miepython}: A Python library for Mie scattering calculations},
  url     = {https://github.com/scottprahl/miepython},
  doi     = {10.5281/zenodo.7949263},
  year    = {2025}
}

License

miepython is released under the MIT License.