Plane diffraction grating

[bassistTech]

Greetings. What a nice package!

I would like to mention that I am experimenting with adding a plane diffraction grating to Optiland. I have been successful at adding one by modifying the standard surface, and as a result, I've learned a lot about the structure of the package. But I believe while it appears to be mathematically correct, I implemented it in the wrong way!

I think that I should work on it some more before forking the project and issuing a pull request. This would be my first contribution to an open source project. But at least I want you to know that someone is working on this. I also have my own little ray tracing package at my repo, but I think yours is much more advanced.

This is just a preview of Optiland with a grating:

[HarrisonKramer]

Hi @bassistTech,

Thanks for opening this!

This is really nice! We have been discussing implementing diffractive surfaces, but hadn't got around to it yet. It would be great if you want to generate this new surface type and submit it in a PR. I would recommend that you start by creating a new module, e.g., diffraction_grating.py and implementing a new class, e.g., DiffractionGrating. You could use ParaxialSurface as a template. If possible, it would be great if it were also compatible with non-planar surfaces, but if that's too complex, then starting with a plane is a great start. There will be a few other changes required before users can (easily) use the new surface, but that can go into a separate PR.

I am happy to help with any of the work, or guide you a bit for your first contribution, if needed. You can just reach out here. Also, I took a look at your ray tracing project. Looks quite nice and has a lot of features already!

Best,
Kramer

[bassistTech]

Kramer,

Thanks for the encouragement. I won't be super quick, since I have a few other things going on this month. But I will try to make progress.

Now that I know my way around the code a bit better, I'll able to do things more cleanly, and take a top-down approach. My existing work isn't wasted, and I'll be able to transfer most of it to my next attempt, but hopefully in a more organized fashion.

Francis

[ivk1223]

Hi Kramer & Francis,

Just new to this amazing project.

I am currently learning optical design and I have share the same interest in such diffractive surfaces but I have very few knowledge in raytracing and dont know where to start.

It is possible if some references or guidiances could be shared regarding how to implement diffractive surfaces in raytracing or in Optiland?

Thanks!

[bassistTech]

This is Francis. I volunteered to add a diffractive surface to Optiland. This is my first time contributing to an open source project, so I'm proceeding carefully. I've forked the project but have not pushed anything to it yet. I'll try to do that this weekend. Here's what you can expect to see:

There will be a branch called plane_grating, where I've implemented the simplest plane grating surface, with uniform groove spacing. I think my implementation works. I've added a notebook that runs through a couple of demo's, including a basic Czerny-Turner spectrograph. I also added a file in docs/references with an explanation of the math.

Like I say, all of this should appear in my fork this weekend. I have some things coming up in my life -- you'll notice that my repo revolves around my alternate life as an amateur musician, and I also have some vacation trips planned, but I hope to submit a real pull request within the next few weeks. Meanwhile I think my fork should at least show you the direction I'm headed in, and how I've made the math work.

Francis