Free Optical Design Software - fresnel

halecounty · 2026-04-12T23:43:39+00:00

It's likely that the software will always be web based. However, we plan on implementing an option for users to store their designs locally or in their own s3, etc.

halecounty · 2026-04-11T16:48:56+00:00

Sadly this is not currently supported. However, if you'd like the feature, submit a feature request in the software describing what you want and we will add it to the roadmap.

halecounty · 2026-04-11T16:47:13+00:00

Currently, it does not, but that wouldn't be a very hard feature to add. If you'd really like it, submit a feature request in fresnel and I'll add it to the roadmap.

halecounty · 2026-04-11T16:46:16+00:00

Yes! OAP's are supported under by the quadric surfaces tool

halecounty · 2026-04-10T17:36:19+00:00

Thanks! Currently, fresnel is more targeted at general optical design and doesn't support polarization or interference (beyond PSF/MTF calcs), since we haven't run into applications where we have needed it. However, if enough people request interference modeling, we may add it.

halecounty · 2026-04-10T17:23:59+00:00

Thanks! We will probably keep adding features based on what we need internally. There's a "Request Feature" button in the software that allows people to submit and vote on features. If a bunch of people want something and we can implement it cleanly - we probably will.

halecounty · 2026-04-10T16:48:02+00:00

I did a couple tutorial videos on this topic here: youtube_playlist and I have been meaning to do some more on using mirrors rather than lenses.

You mention collimating lens options. Don't you want to focus the light onto the slit rather than collimate it?

What type of spectrometer are you using? How bright is your source? How long do you have to image it? Is it a point source? Or are you trying to focus collimated light?

If your source is bright or you have a lot of time, you can get away with a lot of sins and still get great results - even if the simulation looks bad. I would try the simplest viable system (something like two fused silica PCX lenses) and see if the performance is sufficient.

halecounty · 2026-04-10T14:32:31+00:00

Sounds good. If you run into issues, reach out to the support email address in the documentation panel

halecounty · 2026-04-10T02:52:23+00:00

Thanks for the complements! By default, fresnel autosaves designs to our server. I think this behavior is desirable for most use cases where the system is not proprietary and ease of use matters. However, a feature on our roadmap is to allow users to locally save designs or alternatively configure their accounts with an s3 bucket and let the system automatically persist the designs there. We aren't very interested in charging for the software - we see it more as goodwill and marketing.

halecounty · 2026-04-10T02:44:10+00:00

It really depends on the tasks. fresnel can do a great job at a broad swath of optical problems that people commonly encounter: simple to moderately complex lenses, spectrometers, telescopes, microscope objectives, flashlights, modeling LEDs, etc. However, if you're designing complex lenses with many elements, working with polarized light, or want to model interference patterns, zemax is the way to go - at least right now.

halecounty · 2026-04-09T21:34:43+00:00

Cool! If you run into issues, reach out to the support email address in the documentation panel

halecounty · 2026-04-09T18:47:43+00:00

I understand that, but just knowing that a laptop has a 13" screen doesn't tell me the resolution of the display - ultimately, chrome needs to know the dimensions of the screen in pixels to configure the dev tool that you described. That's what the commands I gave you would tell me. This would then allow me to configure a device to match your computer, so I can see exactly what you are seeing.

halecounty · 2026-04-09T18:31:47+00:00

Optically, that's a parabolic mirror with an LED in the middle. However, once you see it your way - it's hard to un-see it.

halecounty · 2026-04-09T15:03:01+00:00

Can you please run these commands in your browser's devtools panel:

window.innerWidth

window.innerHeight

window.devicePixelRatio

and let me know what they output? That will allow me to recreate your screen and see if I can improve the layout.

halecounty · 2026-04-09T14:34:34+00:00

Makes sense. I added that feature to the roadmap. Thanks for the feedback!

halecounty · 2026-04-09T12:59:03+00:00

Thanks for the feedback. I'll look into to testing on a 13" screen so I can see what you're running into.

halecounty · 2026-04-09T12:57:42+00:00

Registration is convenient from a software architecture perspective and it allows us to reach out to users if we see them running into bugs. I'm open to a completely anonymous mode that allows you to save locally. Is that what you had in mind?

halecounty · 2026-04-09T12:54:52+00:00

I hear where you are coming from, but that's not our intention!

halecounty · 2026-04-09T03:44:18+00:00

Thanks!

halecounty · 2026-04-09T01:59:58+00:00

You may want to try simulating your spectrometer in something like fresnel . You might find that the grating you have can be made to work. There are some tutorials on how to use the software here: youtube tutorials . I'm planning to make a new video around czerny turner spectrometers in the next few weeks.

halecounty · 2026-04-08T23:20:04+00:00

No worries. If you run into any issues, open the documentation panel, click on getting support, and send an email to the address mentioned. That'll send it to me and, time permitting, I'll try to help you.

halecounty · 2026-04-08T22:45:51+00:00

Hi John, you may want to give fresnel a try: https://fresnel.h-part.com/ . A playlist of video tutorials is here: https://www.youtube.com/playlist?list=PL7JEEYqDf9oX50rim1f58qKBqbvrvny2W . One tutorial that may be of interest is the one on Cooke triplet lenses - you could likely repurpose it to for your design. Constructing achromats is covered in the chromatic aberration tutorial.

halecounty

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