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Thread: computer created holograms

  1. #1
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    Default computer created holograms

    Some very impressive printing technology has recently been developed, combined with computer software to create interference patterns (for the printer) from photos, animated sequences, and 3D (CAD) models.

    Thus, synthetic holograms are now reality. And they appear to be superior to analog holograms - more control, wider viewing angles and greater depth.

    See the short videos below of brilliant, white light viewable, full color holograms created from CAD models. Over 10 inches of depth.. so the actual hologram will be much more impressive than the video.

    http://www.youtube.com/watch?v=_9QR3qaK_Cs

    http://www.youtube.com/watch?v=6AVAzGQMxEg

    Above from:
    http://www.zebraimaging.com/products

    Rabbit holes:
    http://www.rabbitholes.com/

    Rabbit Holes enables anyone with an interest can have a custom hologram created. Yes, they are expensive, though damn impressive!

    Video of some Rabbit holes animated holograms:
    http://www.youtube.com/watch?v=ocQTQIlRN1Y

    Below is a video of their printer in action - it appears similar to a lightjet printer. Three lasers slowly embed the hologram into the photographic emulsion. And, as lightjet technology, this will assuredly remain a specialized and expensive printing technology. A large holographic emulsion prior to printing is very expensive.

    http://www.youtube.com/watch?v=tVk5-6thgC4
    Last edited by FloggedSynapse; 02-14-2012 at 17:46.

  2. #2
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    computer generated holograms are no new thing, i was making them in 1981!!!! program in C runnning on a vax. produced a cylindrical lenses or a grating about 1 inch square.
    took around 48 hours to run . then had to be electron beam etched onto a glass plate. proved the practical aspect. nowadays should be a cinch nowadays with improved computing power and even nanometer displays. maybe i should get back into it. still got the original paper on it somewhere.

  3. #3
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    Yep maybe U should,....sounds like just what the Dr. ordered for taming high power LDs.
    Cheers

  4. #4
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    well ours where more for infrared optics, used to make visible spectrum holographic optical elements using DCG (Dichromated Gelatine in case its out of fashion) very very efficient (look up LANTIRN) but could be fiddly to make as DGG is a bit of pig to work with so we where investigating other methods. worked on photo resist etched stuff and germanium elements for the ir. Probably wrote one of the first cgh programs around , wish id kept a copy !!!!! i could probably tweek it up no end these days. any way idea let us to think about CG animation in Holography easily possible i think but at the time computers didnt have the horse power, neither could we find a display medium with a suitable resolution or fast enopugh refresh rate. now i can source both!!!! so i am very tempted to go into the CGH animation business, just gotta find the time!
    Last edited by Fijilasers; 04-12-2016 at 15:51. Reason: spelling

  5. #5
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    Default

    Rabbit Holes went out of business a few years ago. Another producer is Geola. Here's a computer generated image I helped make in '88. The image was rendered on a Commodore 64 (IIRC), the master transmission hologram recorded on a silver-halide plate, and the final hologram was in dichromated gelatin on a film base. It was not sealed, put it into this plastic holder in the early '90s, and it's still here 28 years later! DCG usually needs to be hermetically sealed to keep the image from disappearing because of the ingress of water vapor.

    Click image for larger version. 

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  6. #6
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    Quote Originally Posted by Eidetic View Post
    .......The image was rendered on a Commodore 64 (IIRC), ..... ...........Click image for larger version. 

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    ...original image rendering or final output scan to master rendering.
    Final master scan using what delivery system, laser colour etc. ? (inchworm translation stages?)
    Interesting !

    Seems to me that a short FL collimating lens could be integrated with expansion cylinder lenses for any given wave length and could be calculated and written to a robust photo-resist master fairly easily and cheaply for anyone with the right gear available... sadly not me!

    This would be quite a bombshell for diode beam shaping for laser projectors!
    Cheers

  7. #7
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    very nice dcg, but i think we are talking about a different thing. im talking about completely constructing an artificial image by calculating the positions and phase angles of each wave as it would be recorded on the plate then creating a surface hologram using an electron beam etcher (like used for cpu design) . there is never any real physical object, as i think you have here. what algorithim did you use to calculatete wavefront on the plate? what language was it written in . if you did create the wave front using a computer and you have the original code id be extremely interested. how long to create the data file?

    as for diode beam shaping, we never had them back then but yes id think it would be very well suited individual 'lenses' can be made cheaply for any type of beam spread and mode. pretty easy as well id say.
    Last edited by Fijilasers; 04-12-2016 at 12:21. Reason: addition

  8. #8
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    Had a feeling that might be the case !
    Do you know anyone with the gear and the inclination to actually DO this?
    Cheers
    PS. I only know people like me ....EX-holographers !

  9. #9
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    maybe, its not to difficult all you need is the wave front of a cylindrical lens , which is what we produced. you would need some one who is good with math, fourier transforms etc. a cylindrical lens is probably the simplest one to do. my maths not great i did the coding and stuff once the formulas where devised. there may well exist formula on the internet. then you have to convert them to computer code that will produce effectively an x,y grid containing the interference fringes that can be etched or otherwise put onto some optical transparent surface. it should even be possible to make the thing just work at one wavelength so other wavelenghts go through unchanged but thats probably over the top for diodes. Relatively easy to create holographic lenses using DCG or other mediums as well, just do a transmission holo of the lense you need ( have to have one in the first place) then bang out lots of reflection copies. maybe that would do what you want. its what we used to do for our visible elements in dcg.

  10. #10
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    Click image for larger version. 

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ID:	49783 What I had in mind is a wee bit more complicated maths wise!
    The idea would be to "integrate" both the 2mm fl aspheric collimator lens AND BOTH the two cylindical lenses into a single wavefront pattern, so that with a single element all three optical elements could be replaced by one sole element.
    This can ONLY be achieved for one given wavelength and optical setup.... and YES the maths is very complicated...a bit more than just a simple Fourier transform involved here.
    Fortunately their are a few highly capable "brains" in the world who can manage this kind of a thing.(not me)

    However what might be more of a problem, (once the maths have been sorted) is finding someone with the gear and the coding ability to "etch" or "scan" the master itself,.......... do you know anyone with this gear.

    The element itself would need to be similar in size (approx 5mm diameter) and be located in same position as the first aspheric lens, and the two following cylinder lenses would be holograms ("virtual projections") from that same element.

    Cheers

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