Optical aberrations and Zernike Coefficient Computations in COMSOL Multiphysics - Optics Tutorial

#comsol #finiteelementanalysis #finiteelementmethod #optics #raytracing #optics #opticalengineering
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This is the second video in a series of videos on optics and ray tracing in COMSOL Multiphysics. In this video, we explain how to compute the wave-front aberrations and Zernike coefficients in COMSOL Multiphysics. The first part of the COMSOL tutorial can be found here: aleksandarhabe...
Other COMSOL optics tutorials can be found here: aleksandarhabe...

[@aleksandarhaber]

It takes a significant amount of time and energy to create these free video tutorials. You can support my efforts in this way:
- Buy me a Coffee: www.buymeacoffee.com/AleksandarHaber
- PayPal: www.paypal.me/AleksandarHaber
- Patreon: www.patreon.com/user?u=32080176&fan_landing=true
- You Can also press the Thanks TH-cam Dollar button

[@siyuanhou1356]

thank you,that video helps me a lot!

[@kikito6316]

Thank you for your posting about comsol. It's a very helpful tutorial material.

[@aleksandarhaber]

Thank you for your interest and comment. Good luck with your studies.

[@cahitatlas]

Thanks Aleksandar 👋🏼💫

[@aleksandarhaber]

You are welcome

[@AvnishKumar-sg4sj]

Bundle of thanks from a student

[@aleksandarhaber]

Sincerely thank you for the encouraging comment!

[@aleksandarhaber]

The first part of the COMSOL tutorial can be found here: aleksandarhaber.com/ray-tracing-with-comsol-first-part/
Other COMSOL optics tutorials can be found here: aleksandarhaber.com/optics-with-comsol/

[@maxwellconniff1189]

Amazing! Thank you much.
Do you happen to know if the ray optic simulations are particularly slower on AMD processors? Or if COMSOL uses MKL?
My system should theoretically be faster than the one you're using in the video. But after all is done, if I go to "study" to compute again, it takes 198 seconds!
Oy vey. Would you mind letting me know the value you have for these few preference settings in COMSOL?
Preferences:
Graphics and Plot Windows
>Rendering
>Optimize for:
>Antialiasing:
>Detail:
Multicore and Cluster Computing:
>Number of cores:
>Memory Allocator
>Memorayscalability optimization for assembling:
>Scheduler type

[@aleksandarhaber]

These simulations are performed on a 4-year-old laptop computer with 16GB ram. Possible issues can be that you specified too many rays from the release plane or your mesh might be too dense.
I do not know what is the issue. I am just using standard settings. I erased the original file, so I cannot retrieve the data you are asking for.
I am not able to answer these questions simply because I do not know the answers. I think that the best strategy is to send an email to COMSOL support. They are really excellent at what they are doing. Good luck!

[@safaoptics]

Thank you ..I follow your procedure and I've got an error in presenting optical aberration when click on plot an error message "out of memory xmesh processing " what is the problem ?

[@aleksandarhaber]

Probably, you have problems with memory, probably your mesh is too dense
www.comsol.com/forum/thread/30558/Out-of-memory-in-mesh-processing

[@medoabotalb5409]

can you please make a tutorial for reflection?

[@aleksandarhaber]

Medo, I do not have enough time now to make such a video.Sorry...

[@dhoomsaad4406]

Thanks for this clear explanation, but I have a question, how did you get the f=86.2069? , because R2-R1 makes the denominator equal to zero. R2 = R1 = 125

[@aleksandarhaber]

This is because in geometrical optics, there is a sign convention when entering the values in the Lensmaker's equation. This depends if the front/back surface of the lens is convex/concave. The value of R_{2} is entered with a negative sign in the equation, and this gives R_{1}+R_{2}

[@dhoomsaad4406]

Now it's clear. Also, how can I place the solar cell as a heat source instead of the point in comsol? I searched a lot and did not find a specific way to do that. There were a lot of people talking about (Bidirectional coupling), but there is no explanation with examples. Thank you so much.

[@aleksandarhaber]

@@dhoomsaad4406 There is a tutorial on how to couple thermal deformations of optics with ray tracing, and how to model the refractive index changes due to the temperature increase, see for example www.comsol.com/blogs/modeling-thermally-induced-focal-shift-high-powered-laser-systems/
That tutorial is about bidirectional coupling. However, in the case of solar cells, I am not sure that this tutorial will be useful. Best, A. Haber

[@kunalgupta6787]

But how does getting the hemisphere tell us the focal plane distance from the lens?

[@aleksandarhaber]

The reference hemisphere is used to define wave-front aberrations. It is not used to find the focal distance. COMSOL automatically centers this reference sphere at an approximate location of the focal plane or where the RMS of the beam diameter is smallest. You can actually shift the center of the hemisphere as you wish.
Look at my previous videos for approaches to precompute the focal plane.
The first part of the COMSOL tutorial can be found here: aleksandarhaber.com/ray-tracing-with-comsol-first-part/
Other COMSOL optics tutorials can be found here: aleksandarhaber.com/optics-with-comsol/

[@ayaabbioui2289]

Can you please do Shack hartmann wavefront sensor im struggling with microlens array and the oblique wavefront I don't know how to do it 🥺 and thank you for this tutorial 💕

[@aleksandarhaber]

Currently, I do not have time to do that. However, it is an interesting problem.

[@ayaabbioui2289]

@@aleksandarhaber I hope you will consider it ! Thank you again new follower 👍💕

[@aleksandarhaber]

@@ayaabbioui2289 thank you!