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Thread: World’s Largest Depth of Field Laser Hologram

  1. #11
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    Quote Originally Posted by 300EVIL View Post
    I understand that.... I meant the size of the plate. Looks lke they used a Krypton laser for that. I doubt a single he-ne would have the power for that exposure.
    That sir, based on experience, would be a JK Lasers Ltd ruby, a oscillator with a etalon, pulse picked and Q-switched by a Pockels cell, and a amplifier stage or two. Had the pleasure of repairing a double pulse one used for breast cancer detection. Cap bank, on the one I worked on, is the size of 4 industrial steel storage cabinets. Spatial filter pinholes were gem grade diamond, and if misaligned the oscillator alone would ablate chunks of diamond. Rods were a good 6-8 inches long. One shot every 2-3 minutes.

    I imagine they waited a hour between shots, and it would not shock me if the "bar" was in a coal mine or something. On the other hand, things don't move much in a millisecond.

    Steve
    Last edited by mixedgas; 08-09-2010 at 15:49.
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  2. #12
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    What Paula actually did was to have a simulated New Year's Eve party with 60 guests in the bar which was constructed full scale in a hologram recording studio. At regular intervals throughout the evening, all the guests simultaneously set their possessions down and left the bar while regular photographs were taken of the scene.

    Each scene was later set up according to the photos, with the pieces attached and/or modified slightly to make them stable. The holograms were shot on film mounted to a vacuum plateholder, using a large frame Krypton laser at 647nm. Don't remember the exact settling time or exposure time, but I'd guess 30 minutes to settle and a few minutes for exposure in '87 with Agfa 8E75HD film. I'm certain she left everything in the bar sealed overnight before the exposure. Regarding stability for making holograms, I have to say it's overemphasized. Most of the time you can just take the laser head with the water flowing through it off the table, de-float the table, and don't jump around when the shutter's open! Most of the time it's air currents that make the holograms dim. Paula's work demonstrates this.

    I must say I've seen lots of holography in the past 30 years and this is easily in the top ten, top five for really showing the magic capable of the medium.
    Last edited by Eidetic; 08-09-2010 at 17:21.

  3. #13
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    [QUOTE=robert hess;158442]What Paula actually did was to have a simulated New Year's Eve party with 60 guests in the bar which was constructed full scale in a hologram recording studio. At regular intervals throughout the evening, all the guests simultaneously set their possessions down and left the bar while regular photographs were taken of the scene.


    OK, I educated guessed wrong. Large frame KR would do it, if you had a very good one.

    Steve
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  4. #14
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    Talking Hologram fun

    Tommy Johnson's doing something like this; he has a 315M,
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    and is working on a doubled FPSS oscillator/dual amp for portrait holograms.
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    Progress can be followed here (scroll way down):
    http://www.bobdbob.com/~tjohnson/lab/

    He also has helped me with my laser misadventures, spotted variously:
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    and some LED stuff.
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    And I helped him install his optical table (don't try this at home!)
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    and some Acrylic stock.
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