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Thread: computer created holograms

  1. #11
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    sounds fine, if you can get the maths done. etching wise id think any of the chip manufacturers can do it, i know we used a custom chip manufacturer years ago. they dont care really what it is they are etching and as long as they have the resolution it should work, you could make a master then use that to stamp out many copies. dont personally know any one but im sure there not to hard to find. combining all the elements in one is really the whole point , and reducing manufacturing cost. 5mm dia is tiny so production should be cheap.

  2. #12
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    There was no object used for making the hologram I posted. The image was created in the computer, and sequential perspective views recorded as sequential slit exposures on the transmission hologram master. But while it's correct that it isn't what's being discussed now here, it is the technique described in the original post (though a two-step technique instead of a one-step as done by Zebra Imaging).

    I think the problem with surface relief gratings as described would be that the diffraction efficiency would be very low. Also, in-line geometry would be difficult without using multiple gratings. Volume materials like DCG would have higher DE, but wouldn't be etched.
    Last edited by Eidetic; 04-15-2016 at 09:16.

  3. #13
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    ... anyone experience with generating computer-holograms?

    I have enough micro-/nano-gear to build and control a XYZ-stage with sub-micron resolution and some fiber-lasers with 1070nm wavelength and with beam expander down to 7 microns smallest spot size ... best spot-size with 405nm-diodes is 30microns, but only some hundred Milliwatts of power.

    Could be interesting to DIY transmission holograms from glass plates coated with carbon or silver ...

    Viktor

  4. #14
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    Here's another holographic stereogram from Advanced Dimensional Displays in 1989. The image is called "Lovely Rita", by Craig Newswanger (now at Zebra Imaging). I worked with him there on a full color version, and made this particular one as part of a test roll. As the disk rotates, she opens her robe (while rotated away from the viewer) and closes it again. Originally produced around 1985, the image is still one of the most famous and sought after holograms ever.

    Click image for larger version. 

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    And this is a full parallax holographic stereogram I made in 1995. It shows a 3D image in both vertical and horizontal directions, and the images on the TVs animate as one moves up and down in the viewing zone. This image was also created on a computer (by Brian Kane). It's an example of a two-step technique to make a hologram as is described in the videos posted above.

    Click image for larger version. 

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    Last edited by Eidetic; 04-15-2016 at 09:39.

  5. #15
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    Lightbulb ..bit off-topic, but..

    Heya Fellas -

    Any of you Holo-experts know of a good 'mastering house' for getting custom transmission-holos done? I mean for something like this:
    ..in that, it's a 'custom image' - in this case, it will be a simple URL, not and entire keyboard, etc.. But the concept / desired output is the same..

    ..Got a Client-request to make some biz-card-size films with a transmission-holo of a URL text.. I used to have a contact at a house in Toronto, from one I had made for a job a zillion years-back, but.. All that info is long-gone, so..

    Any help / direction? Mucho obligado..

    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  6. #16
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    Hi Jon

    If you 'do' Facebook you may want to take a look here...

    https://www.facebook.com/groups/Holography/

    There's a huge wealth of knowledge there and in all probability some folks who may be able to assist you further.

    Cheers

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.”... Douglas Adams 1952 - 2001

  7. #17
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    Cheers, Jem! Thanks, I will check that out / post up an 'RFI'...

    j
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  8. #18
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    ... we're discussing in a German laser-forum about getting/making custom gratings in single counts or DIY (comercial manufacturers only starts form 5000USD up).

    Then I've remembered an old post about the same and the advice to use ImageJ (http://imagej.nih.gov/ij/) to create FFT-grids, which can be printed on/into transmission films and act the same like gratings to 'recreate' the original object.

    For easy DIY I've tested the smallest/coarsest FFT-calculation and binary analogon, which will recreate to a recognizable image.

    Attached is a test with a simple sketch, the calculated FFT-grid, binary conversion, and reverse FFT calculation ... if this will work, then this could be a cheap alternative to DIY gratings ...

    Viktor
    Attached Thumbnails Attached Thumbnails Test2-FFT-DOE.png  


  9. #19
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    ... this could be interesting too - did some reducing ("binarysation") and smoothing with the 16x16-FFT-grid - pairs of changed FFT-grids and the resulting reverts:
    Attached Thumbnails Attached Thumbnails Test2-FFT-DOE2.png  


  10. #20
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    ... hmmm - could be working ...

    I've tested a 445nm-diode with standard collimator, set to strong divergent beam with 'beamsize' of maybe 40cm in 1.5m distance.

    Here the images of the 'pure' beam .. and an etched metal sieve with 100 micron big holes in a 200 micron grid placed into the beam some mm away from the focus:

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    ... and then I've fed the beam through a 1mm glass fiber to 'homogenize' it and a lens to set it to a similar diverging beam with roughly 50cm diameter in 1.5m distance ... and made images with the pure beam and two pieces of the same sieve to get a moiré-grating:

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    ... so could be working with 20 micron big 'dots' or cavities too ...

    Viktor

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