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Science Forum Index » Optics Forum » Computer Generated Holograms for Testing Optics
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| Neal Shepard |
 Posted: Thu Oct 30, 2003 8:28 pm |
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Here's an intriguing technique for testing parabolic mirrors. Instead of an
expensive reference element, a hologram is used in a Twyman-Green
interferometer.
Anyone used this method or can point be to software to generate the
holograms?
NS |
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| Rene Tschaggelar |
| Posted: Fri Oct 31, 2003 3:18 am |
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Neal Shepard wrote:
Quote: Here's an intriguing technique for testing parabolic mirrors. Instead of an
expensive reference element, a hologram is used in a Twyman-Green
interferometer.
Anyone used this method or can point be to software to generate the
holograms?
How would you want a computer generate the hologram ?
A hologram is an interference pattern on some relective or
transparent film. Its resolution is much better than of the
wavelength to have structures with the size of the wavelength.
A printer needed in the order of 50'000 dpi to reach 500nm.
Oh, shrinking a bigger image ? With visible light ?
Rene
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| Jens Kilian |
| Posted: Fri Oct 31, 2003 7:11 am |
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Rene Tschaggelar <none@none.none> writes:
Quote: How would you want a computer generate the hologram ?
Electron-beam lithography, for example.
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| Neal Shepard |
| Posted: Fri Oct 31, 2003 11:52 am |
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You can search papers by James C. Wyant He describes plotting them out 70cm
and shrinking them to 1.2cm as one example. These patterns may be
rectangles and need not be as complex as the usual holograms for 3D.
Hope someone whos taken optics courses (certainly at U of Arizona) can help
out with software.
NS
Quote:
How would you want a computer generate the hologram ?
A hologram is an interference pattern on some relective or
transparent film. Its resolution is much better than of the
wavelength to have structures with the size of the wavelength.
A printer needed in the order of 50'000 dpi to reach 500nm.
Oh, shrinking a bigger image ? With visible light ?
Rene |
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| Alexander Dräbenstedt |
| Posted: Fri Oct 31, 2003 5:48 pm |
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"Neal Shepard" <Neal@nospam.com> schrieb im Newsbeitrag
news:vq54r56p19gj37@corp.supernews.com...
Quote: You can search papers by James C. Wyant He describes plotting them out
70cm
and shrinking them to 1.2cm as one example. These patterns may be
rectangles and need not be as complex as the usual holograms for 3D.
Hope someone whos taken optics courses (certainly at U of Arizona) can
help
out with software.
NS
How would you want a computer generate the hologram ?
A hologram is an interference pattern on some relective or
transparent film. Its resolution is much better than of the
wavelength to have structures with the size of the wavelength.
A printer needed in the order of 50'000 dpi to reach 500nm.
Oh, shrinking a bigger image ? With visible light ?
Rene
Real computer generated holograms that are useful for the purpose that I
think the OP is speaking of are mostly written in LCD displays, especially
the ones used in video projectors. You can find some material about CGHs and
optics testing against virtual reference objects at the 'Institute of
technichal optics' at the university of Stuttgart.
http://www.uni-stuttgart.de/ito/Forschung/Inter1/interfer.html
http://www.uni-stuttgart.de/ito/ito_www_old/index.html
Sorry, most of it is possibly in german.
Alexander |
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| Henry Nebrensky |
| Posted: Mon Nov 03, 2003 2:22 pm |
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There's something called 'holocrunchies' (!) on sourceforge.net.
I've not got round to trying it yet, so I don't know if it
can deal with arbitrary wavefronts directly, though.
Henry |
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