FFTs and Optical Lenses

Re:FFTs and Optical Lenses by neltnerb on Tuesday May 27, 2014 @09:23PM (#7807893)

I think the most memorable thing I learned in quantum mechanics is that quantum mechanical scattering is also exactly the fourier transform. Suddenly braggs law became much more sensible.

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Re:FFTs and Optical Lenses by frozenport on Wednesday May 28, 2014 @12:27AM (#7808412)

>>is also exactly the fourier transform

No, this is only under the 1st born approximation, in the far-field and without the 'dish' shape intrinsic to propagation. A lot of times this model doesn't work. Also now you are in the momentum space which doesn't map immediately to the x,y,z coordinates you might have started with. Also the evanescent fields that the Ewald sphere didn't include...

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Re:FFTs and Optical Lenses by neltnerb on Wednesday May 28, 2014 @03:43AM (#7808856)

Hehe, well, thanks for the correction. Yes on all of these things, I'm sure.

I should have said "the exact solution for the most basic justifiable approximation". Honestly, it's been 9 years since I last did quantum seriously, so that was the extent that I remembered.

Deriving Bragg's law in front of my quals committee and refusing to use "mirror planes" despite it being a Materials Science Ph.D. was just viscerally satisfying. It may not have been absolutely correct math, but at least it was way more justifiable than the typical accepted "solution" in my field =)

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