Why does a lens perform a fourier transform on light? Literaly

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I have no ideia. I just wanted to share this pic.

I hope you like my reply.

>>8653919
https://en.wikipedia.org/wiki/Fourier_optics#Fourier_transforming_property_of_lenses

>>8653938
I already went through the derrivation it doesn't explain jack shit

>>8653949

you must be a brainlet

>>8653978
>implying you know the answer

>>8653919
Fermat's principle

>>8654126
Did you even read the question?

>>8654186

different wavelengths travel through the medium at different speeds so they take a different path

>>8654201
But this happens for monochromatic waves.

>>8654205
Since when?

>>8654288
Since forever?

fat fourier transform

>>8654205
They're not monochromatic. If the wave canbe represented as a superposition of monochromatic ones, it will behave like its individual components

>>8654538
What are you talking about monochromatic waves still undergo a fourier transform when they pass through a lens. I want to know why.

>>8653919
I think the answer is 'it just does'.

>>8654538
OP is talking about spatial frequencies, not temporal.

>>8653919
>>8653949
I can give you a qualitative answer. A lens focuses a plane wave into a single point, i.e. the same as the Fourier transform, which turns a plane wave into a delta function. Why it holds in general I don't know.

>>8654400
nice signal analysis joke

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>>8653919
>>8653938
Wait, is this what those astroturfs are talking about when setting up telescopes a large distance apart from each other and saying it will increase their resolution by doing some Fourier shit?

>>8655383
Is it just a coincidence that the relation is a Fourier transform? Or is there something more fundamental that I'm missing?