How to get Gaussian Laser with Divergence (Gaussian Beam)

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CeDoMain
Posts: 1
Joined: Thu Feb 17, 2022 1:56 pm

How to get Gaussian Laser with Divergence (Gaussian Beam)

Post by CeDoMain »

Hello guys,

for a research project i need to simulate a gaussian laser beam with small divergence.
Currently i simulate the gaussian beam with multiple area lights in different sizes and power in "laser mode".
I have approx 20 lights for one beam, generated by my script.

Now i need more lasers (50) and also the ability to diverge (0.01°) the beam slightly.
Because 50 lasers with 20 lights each is very inefficient to render i search for another approach.
I tried spot light, but it seems only an angle (Size parameter) of 1° is possible.
So i think i have to stick with the area light. The area light can do an "spread angle" of 0.005° so it seems ok.

My Questions:
If I switch to Shape Disk i get a message "unsupported shape". Any drawbacks if I use this setting? What does this internally mean?
How can i efficiently get the gaussian intensity distribution? IES lights seems to not work with such small angles.

What I CAN do, but this is not preferred (beacause its mathematically heavy): Use an area light in "laser mode" and generate a lens (or lens system) which generates a gaussian beam.
FYI: You can find the mathematical description for a gaussian beam here: https://en.wikipedia.org/wiki/Gaussian_beam
If you are german, read the german one - it seems better to me.

EDIT: I know that its appreciated if I upload a testscene. In my opinion its not helpful since I want to know "how to archive something the easiest and performant way". But if you need something please text me and I will try to upload this.

Thanks for your help!
CeDoMain
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