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Re: De-screening



In article <NEBBKHCFDGIGIJEHDJFCCENADEAA.pderocco@ix.netcom.com>, Paul 
D. DeRocco <pderocco@ix.netcom.com> writes
>Kewl. How do you do an optical Fourier transform?
>
Probably a lot easier that you thought, Paul - you do it all the time! 
:-)

An ideal lens is a real time Fourier Transforming device.  The image 
formed by the lens is just an FT, scaled by wavelength, of the light 
intensity across the lens stop.

That is why, in a perfect lens, the image formed by a monochromatic 
point source is the well known Fresnel diffraction pattern - the FT of 
the circularly symmetrical lens aperture.

Many textbooks have been written on this topic, but a couple worth 
looking at if you want to know more are:
JW Goodman : Introduction to Fourier Optics published by McGraw Hill and 
JD Gaskill : Linear Systems, Fourier Transforms and Optics, published by 
John Wiley.
-- 
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers
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