Modeling of SCExAO

Building the actual thing is not enough: a numerical model of any experiment is also essential to understanding what's going on inside... SCExAO doesn't escape this general rule and we are working on this model these days!

Doing this is always very interesting and really makes you think about the minute details of all of the optics that currently lie on the bench. And SCExAO involves some pretty tricky components: pupil remapping devices like the SRP, the PIAA and the inverse PIAA are really peculiar optics, and the deformable mirror is a surprisingly complex little thing... but we're getting there!

Just like with the experiment control GUI, we've decided to program this model in Python. It's just been a couple months since we started playing with this, but the deeper we dig, the more we find! Numpy, Scipy, Matplotlib and Pyfits form together a great scientific programming environment that, once you get used to it, does just as well as IDL, which I have been using for the last couple of years.

The picture shows the kind of things this simulation produces: point spread functions (PSF) for different off-axis sources (1,5,10 and 20 lambda/D). Although not finely tuned yet, the model nicely reproduces the pineapple-shaped PSFs that SCExAO generates for off-axis sources with the PIAA only, as published by Lozi et al. (2009).