Going to be super busy soon, but to contribute to the community since I have learnt a lot from, I finally found the video when it first came out 2 years ago about how diffractive lens can get you multiple foci (focuses) . . . The title of the video might be "off topic", but the interesting part (for me) is at and after 12:12, so you can skip the beginning and jump to that time mark. When light passes through an aperture, similar things can happen . . . That channel is highly recommended if you are into this sort of stuff, at least I am constantly amazed by the content.
I really like his statement that "Indeed Light Always Shows Up Somewhere Else If You Create Areas Of Destructive Interference"
Interesting Video: Two Foci From A Diffraction Lens
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