Nanophotonics Transfer Matrix Solver

This script builds the transfer matrix for the light incident on a multi-material slab and plots the reflection and transmission as a function of wavelength and incident angle for both TE and TM polarizations.

Materials can be supplied to the sweep function in main.py or are supplied through the file material_input.txt, where each line is of the form “[name],[thickness],[index]” where name and thickness are required, and index is only required for materials not listed in materials.INDICES. You can always supply a value for the refractive index to use a constant value (real or complex) across all wavelengths that will override the default for that material.

If a Material is either “gold” or “silver”, the first line of material_input.txt must be of the form “model=[model]” where model is the name of the model to use for the optical properties of the material and must be one of the following:

• Drude
• Johnson
• Palik

The “Drude” model is a semi-analytical model for the permittivity, while the ”Johnson” and “Palik” models use complex refractive index values interpolated from the values in the books by (i) Johnson & Christy and (ii) Palik.

The images above are plots of transmittance (left) and reflectance (right) for a slab consisting of:

1. 50nm of Ag
2. 100nm of Si
3. 50nm of Au
4. 100nm of Ag
5. 50nm of SiO₂

These can be compared to results for the same stack generated by an online application from Filmetrics: