armmwave

Code that calculates transmittace and reflectance of materials at millimeter wavelengths.

This software was developed to aid in development of anti-reflection coatings for millimeter-wave optics---specifically, for optics used in Cosmic Microwave Background (CMB) experiments. CMB experiments have begun to adopt high-refractive index materials for their lenses. While there are many perks to this optical design, there are also a few drawbacks. One of these is reflection.
High-refractive index materials---such as aluminum oxide and silicon, both of which are used in CMB experiments---reflect a significant fraction of the light that fall on them. To reduce that fraction we create anti-reflection coatings to cover the lenses.

One way to make a coating that operates over a wide range of frequencies (wavelengths) is to stack layers of different dielectric materials. Working out the transmittance and reflectance of a multilayer dielectric structure is a problem that can be handled using the characteristic matrix method. Enter armmwave.

Please note: This code is under active development. While it has been verified against experimental spectroscopic data (~25 to 500 GHz; examples will be uploaded soon), make sure you understand the intricacies of your specific data or model.

Examples

armmwave provides a means to set up and evaluate models of multilayer dielectric media. To do this, create one or more Layer's (with associated refractive index and thickness---and an optional loss term), create a Source layer and Terminator layer (which are required for bookkeeping), and a Model. By default, reflectance and transmittance is calculated between 500 MHz and 500 GHz, but you can change this if you want. Here's an example model of a sheet of ceramic material (in this case aluminum oxide) in a vacuum:

import armmwave.layer as awl
import armmwave.model as awm

# First create a list of layers (dielectrics) in the order
# they should be evaluated
layers = [awl.Source(),
          awl.Layer(rind=3.1, thick=2e-3), # thickness in meters
          awl.Terminator()]
# Now create the model framework, feed it the layers, and run!
model = awm.Model()
model.set_up(layers)
results = model.run()

model.run() returns a dictionary with three keys: frequency, transmittance, and reflectance.

Contribution guidelines

This code is under active development. If you have an idea for a feature or use case, please open an issue ticket. Let's talk! If you have an idea and you've already written the code---that's great! Create a pull request and we can go from there.

Bugs

Let's face it: there are probably bugs. If you find one, please open an issue ticket. Include a description of the issue and, if possible, a minimal working example. I appreciate your patience (and your help).

TODO

• Figure out how to make TravisCI make wheels for me
• Better docs
• Examples