mnpbem-material 0.1.6

Material dielectric models for plasmonic electrodynamics in MNPBEM-Python.

mnpbem-material

mnpbem-material implements dielectric-function models used in plasmonic electrodynamics. The module provides analytical material models and tabulated optical constants for metals such as Au, Ag, and Al.

Features

• Constant dielectric model for homogeneous media.
• Drude dielectric model for free-electron metals.
• Tabulated (E, n, k) optical constants with wavelength-domain interpolation.
• Ready-to-use datasets for common plasmonic materials.

Implemented Formulations

1. Constant Dielectric Function

For wavelength-independent permittivity:

\varepsilon(\lambda) = \varepsilon_0

The wave number is:

k(\lambda) = \frac{2\pi}{\lambda}\sqrt{\varepsilon}

2. Drude Model

For free-electron metal response:

\varepsilon(\omega) =
\varepsilon_\infty -
\frac{\omega_p^2}{\omega(\omega + i\gamma)}

Energy-wavelength conversion used in the implementation:

\omega_{\mathrm{eV}} = \frac{C_{\mathrm{eV\cdot nm}}}{\lambda_{\mathrm{nm}}},
\qquad C_{\mathrm{eV\cdot nm}} \approx 1239.841984

3. Tabulated Material Model

Given tabulated optical constants (energy, refractive index, extinction), the dielectric function is:

\varepsilon = (n + i k)^2

Implementation

• Core implementation: src/mnpbem_material/models.py
• Material datasets: src/mnpbem_material/data/*.dat

Dependencies

• numpy>=1.24

Installation

pip install mnpbem-material

Example

Runnable example:

• examples/basic_usage.py

Run:

python examples/basic_usage.py

Author

• GALIH RIDHO UTOMO
• [e-mail]