Earlier quoted context omitted.
My mind was blown when I saw the 4F experiment, where a lens transforms an image into the Fourier domain. I'm not sure if it's related to the Fresnel zone (I think it is not or only very vaguely), but it's pretty amazing: A widened beam of collimated light (i.e. parallel beams) is sent through e.g. a slide with some image printed on it. Using a lens placed one focal length away, it is focused down to a point (one foc…
Wow! Are you maybe able to find a demo video of this? I'd love to see it! (I'm the author of the post btw)
I think this one showed some of it (I saw it elsewhere, this is just what I could dig up) https://www.youtube.com/watch?v=wcRB3TWIAXE