Author homepage: http://sjbyrnes.com Package home at PyPI: http://pypi.python.org/pypi/tmm Package home at Github: https://github.com/sbyrnes321/tmm This is a group of programs written in Python / NumPy for simulating light propagation in planar multilayer thin films, including the effects of multiple internal reflections and interference, using the "Transfer Matrix Method". It can also simulate combinations of thin and thick films (e.g. a thick piece of glass with a multi-layer antireflection coating on one side and a mirror on the other side), or purely thick films. In addition to calculating how much light is transmitted and reflected, the program can calculate, at any given point in the structure, how much light is being absorbed there. This is a very important feature for solar-cell modeling, for example. It can also calculate the parameters measured in ellipsometry. For more information, see manual.pdf . Get it directly at http://sjbyrnes.com/fresnel_manual.pdf