micromode 0.1.0a1

Rust-backed photonics mode solver with a small Python API.

micromode

A minimal FDFD electromagnetic mode solver for rasterized waveguide cross sections with a Rust core made to be a standard plugin for FDTD engines.

pip install micromode

Why Use It?

• Grid-first API: pass arrays directly, with no required geometry model.
• Rust sparse backend: one production solve path.
• Practical outputs: fields, n_eff, k_eff, mode area, polarization fractions, Lorentz overlaps, plotting, dataframe export, and HDF5 save/load.
• Tensor-aware: supports scalar, diagonal anisotropic, and full tensor material grids.
• Works for both 2D cross sections and 1D slices.

You give it a material grid. It returns guided modes: effective indices, six-component fields, polarization metrics, mode area, overlaps, diagnostics, plots, and HDF5 output. MicroMode is intentionally not a CAD or geometry package. It is the solver piece you use after geometry has already been rasterized onto a mode-plane grid.

Quick Start

import micromode as mm

wavelength_um = 1.55
freq = mm.C_0 / wavelength_um

# Arrays from your own rasterizer.
eps_xx, x_edges, y_edges = mode_plane_arrays(...)

materials = mm.Materials.from_diagonal(
    eps_xx=eps_xx,
    x_edges=x_edges,
    y_edges=y_edges,
)

data = mm.solve_modes(
    material_grid=materials,
    freqs=[freq],
    num_modes=2,
    target_neff=2.5,
)

print(data.n_eff.values)
data.plot_field("Ex", mode_index=0)
data.to_hdf5("modes.h5")