World’s Largest Depth of Field Laser Hologram

[andy_con]

http://www.eevblog.com/2010/08/07/wo...aser-hologram/

hope this isnt a repost

[Jem]

Great Video Andy, thanks for posting it

I dream of making holograms like that... Ah well, perhaps one day.

Cheers

Jem

[andy_con]

were all expecting to see one at the next meet jem

[300EVIL]

HA! Very Cool! I had no idea they made holograms that large. I'd love to see that in person.

EEVBlog is great. Dave is like the Steve Erwin of electronics with his high octane mannerisms in some of his videos. Everyone should check out more of his vids, they are great!

[Jem]

HA! Very Cool! I had no idea they made holograms that large.

Well, the hologram itself is not particularly large. Imagine it more as a window. you only need a small window to see the entirety of the room beyond.

This particular hologram is a 'Transmission' hologram that can only be reconstructed using the same wavelength of laser that was used to create it. The depth of the image is directly related to the coherence length of the laser used to record it.

HeNe lasers may ahve a coherence length of 30cm, whilst a carefully controlled DPSS laser can have a coherence length of may meters. For instance a Coherent 315m or 532 ring laser would both be suitable to obtain images of this sort.

I suspect that this particular image was probably recorded with an Argon laser fitted with an Etalon. However, the image appears to be red, so that would suggest a red laser was used to record the image. Unless of course the image was post swelled so that it reconstructed in a different wavelength of light to which it was recorded.

Cheers

Jem

[300EVIL]

Well, the hologram itself is not particularly large. Imagine it more as a window. you only need a small window to see the entirety of the room beyond.

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.

[flecom]

wow holy crap thats amazing... i have serious respect for people that make holograms... a long time ago when I was a little kid i tried to make some, got some close but they were mostly no good...

did meet some people in miami that were making holograms... they made the visa eagle IIRC

[Eidetic]

The Visa Dove hologram was made in New York by Ken Haines of ABNH, not in Miami. You're probably speaking of Jeff Weil in Miami, who makes masters for embossed holograms like those on credit cards. Ken was one of the early '60s engineers at Willow Run with Leith & Upatnieks when they did their first holography between 1960 and 1964.

[flecom]

sounds about right... think the company was called Holographic Dimensions or something like that

[drlava]

To get the scene and air still after so many people were in the room for the deep bar shots, how long do you think the would they have to leave before the exposure?

[mixedgas]

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

[Eidetic]

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.

[mixedgas]

[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

[DanBarlow]

Tommy Johnson's doing something like this; he has a 315M,
pict0004.jpgmeddscn5965.jpg
and is working on a doubled FPSS oscillator/dual amp for portrait holograms.
pict0002.jpgpict0015.jpgmeddscn6287.jpg
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:
pict0023.jpgpict0025.jpgmeddscn0041.jpgmeddscn1770.jpgmeddscn2604.jpgmeddscn3325.jpg
meddscn3328.jpg

and some LED stuff.
pict0038.jpgmeddscn2403.jpg


And I helped him install his optical table (don't try this at home!)
pict0012.jpgpict0032.jpgpict0049.jpg
and some Acrylic stock.
meddscn2674.jpg