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Making Holograms In The Kitchen
Paul writes "Over at www.litiholo.com is a newly launched
hologram kit that lets
you make your own holograms at home. No, it's not Princess Leia asking you for
help, but it's still pretty cool making a hologram on your kitchen table. Particularly
interesting is the instant
hologram film that makes holograms with no developing (kind of a Polaroid
film for holograms). The hologram kit costs $99, including the laser, film, and
everything else."
You can get it from Amazon. It's Shoebox Holography
The hologram kit costs $99, including the laser, film, and everything else." - what, no shark? it's a bloody rip off!
You can't handle the truth.
Ah well.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
just wait for the porn industry to get ahold of this one! hmnm, wait a minute, seems like porn drives ALOT of industries... nevermind...
According to the web site, you need to use either the laser or a special flashlight to view the hologram. That would seem to limit the usefulness of the process.
Aah. Can't wait for the amateur holo-porn to emerge. Streaming video surrenders.
A sheet of film and a laser pointer, and before you know it you too can be counterfeiting Microsoft and Master Card logos.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
... and what my brain immediately supplied was "I am Lithholio! I need laser for my bunghole!"
Those misspent hours in my youth really are starting to bite me in the ass.
Has sold holography kits for years. Currently they have a book Showbox Holography which shows how to set up a small lab to shoot holograms with a pen diode laser. They used to have a neat kit with a HeNe laser back in the day, but it wern't no $100 bucks. *cough* I haven't looked at an Edmund Scientific catalog for over a decade, but they seem to have shifted from the home hobby lab market to strictly the teaching market... shame. --M
I am not totally sure, but I think the kits sold at the linked site require the use of a laser to view the hologram, they are not white-light holograms. Instead you might wanna check out this site and their hologram kits, I plan on purchasing the Standard Kit. http://www.holokits.com
Note that the author of the article "Paul" is associated with the company (based on his email address). But at least he's honest in not trying to hide that info.
instructions here.
It is ordinary film (in a sheet film format, I used to use black and white 4x5" film that's about $1/sheet in 25 packs.
Basically, to make a hologram you start with a single source of monochromatic and in phase light (a laser), split the beam into two so they will still be in phase and at the same frequency. Then use one beam to illuminate the film directly (referrence beam) and the other to illuminate the object and then the film after bouncing off the object (subject beam).
The result is that you create an interference pattern of lightwaves on the film, and depending on the shape of the object, the waves in the subject beam are delayed by various amounts.
The result is that when light passes through this interference pattern on the film, it forms a real (3D) image of the original object that caused the interferrence pattern.
Jason
ProfQuotes
Neither. The hologram is a function of refracted visible light caused by interference patterns.
So, there are a number of factors that determine the hue of the image...and you get that "oil on water" type rainbow effect.
You *can* make full colour holograms, but the process is complex and requires three lasers (R+G+B) and colour holographic film. Also remember that movement of even just a few microns in the illuminated subject disrupts the interference patter enough to cause foggy exposures ruining your holograph -- so doing it with three laser sources is even more prone to errors.
(Real holography used to be a hobby of mine).
-psy
Today? You must be new here.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
A little Googling shows this to be something called a Hadamard Transform.
In the Early to Mid '90s, fast computers had to churn away to make fuzzy cubes and other simple objects.
With better computers and better printers the rendering should be faster and the reduction phase not as extreme. Also with larger Holographic plates the results should be less fuzzy.
Does anyone know the state of Computer generated Holograms? Real geeks wouldn't make holograms with old fashion photographic plates, but in the guts of their over-clocked AMD boxen.
Letter To Iran
I'm always worried about cutting my fingers off when I'm using a regular LASER.
why do you want long coherence lengths? because you need to make sure that at every point on the film the path lenth difference between every ray you want to capture and the reference beam is within the coherence length. As a starting point one would say that at a minumim it should not be less than the width of the film or the width/depth/height of the object or scene which ever is greater.
Looking at thepicture of the kit, the film and object are many times the cavity size of the a typical internal cavity diode laser. And dhiode lasers have sucky coherence normally.
are there some clever ways of lighting a scene that can minimize the coherence length requirements?
I note that the systemin use is a single frequency hologram not a white light hologram. thus the play back has to be done by a monochromatic light source. It must be the arrangement they are using is not a thick film hologram but a thin film hologram.
any ideas on the geometry they are using and how they are handling the coherence length issue???
Some drink at the fountain of knowledge. Others just gargle.
"What is the nature of your culinary emergency?"
We've been discussing the Liti 'instant hologram' film over at HolographyForum for awhile. The big downside is that these are transmission holograms, and are therefore quite a bit harder to view than reflection holograms. On the other hand, self-developing film is very cool -- normally, you need to develop holograms in a fashion quite similar to photographic prints.
This
Back in the day when school was uphill both ways, we used to make holographs by taking a coffee can with the bottom cut out and wrapping a sheet of AGFA red-sensitive photo paper around the inside of the can. We'd set the coffee can on the table, empty end down, and set a small eraser in the middle. The eraser had a small hollow with a single drop of mercury. Put an item of interest somewhere between the erasure and the film, then illuminate the mercury with a laser that's suspended overhead. Develop, and then view the paper backlit by the laser. Instant holograph!
The effect was very impressive. I guess nowadays, you'd have the most trouble finding mercury...
The really fun stuff is hand-drawn, and all you need is a compass (with two points) and a shiny but scratchable surface. Oh, and a bit of time.
Hand Drawn Holograms.
-Billy
Suprisingly it worked fairly well. We produced a few small holos of toy cars and stuff, using some Ilford film (can't remember which type) a HeNe laser, and guessing the exposure time. Fixing the film didn't seem to work well though - the holograms tended to start fading or something after a few days.
Do kids get to do stuff like this in school these days? I would like to think that cool science things are routinely taught now, since technology like lasers are everywhere. Probably wishful thinking.
This is not a sig
Nobody's going to be making holograms in their kitchen for $99. There are obviously only a few people in this thread who have actually made holograms (people like me). You can tell them because they're all talking about elaborate antivibration systems. You have to kill vibrations down to below the wavelength of light in order to make holograms.
I took a class in holography at my university. We used the research lab in the physics building's basement, using serious research-quality lasers and optics, and an optical table that weighed 2500 pounds sitting on a vibration-dampening cushion, atop a steel and concrete pillar buried deeply into the ground til it hit bedrock. And even THEN, we had to use the lab at about 2AM when the street traffic died down, because even a car driving down the street could induce enough vibration to ruin the hologram.
Eventually the Physics department built a new laser lab next to a riverbank, on a rarely used cul-de-sac on the edge of the campus. That reduced a lot of the vibration from street traffic. Unfortunately, their new multimillion-dollar frequency-tunable laser, the centerpiece of the lab, caught on fire the first time it was turned on, and that was kind of the end of the laser lab.
You don't have to have that much stuff.
I satsified my art requirement as an undergrad by taking a holography as art semi-independent study. I was a physics student, and the other guy taking it was an art student. I don't think he ever managed to make a hologram because he couldn't align the spatial filters. My art sucked, but I had no trouble getting good holograms.
There were two tables-- the small one used a lot of heavy blocks in the base to make it massive, and I think it only had sand for isolation, no air legs, and a half a pool table for a top. The other table was nicer-- it had air legs made form inner tubes (works fine) and the surface was a full sized pool table slate that was resting on a bunch of tennis balls laid out in an irregular 2-D array to avoid creating bad resonant modes.
It was in the basement of the dorm that held the college for lefties (within a much larger university) and part of the room was under a stairwell. Most of the time you just had to make sure nobody had come down the stairs in the last few minutes, and do it at an hour when it was reasonably unlikely that someone would come down the stairs during a 1 minute or so exposure. For super stability, there was a setup using a mechanism from an HO railroad track switch, and you would sit outside the room (so as not to disturb the air inside) for a half hour or so, and then make the exposure.
The hardest part of the whole thing was that the spatial filters were made from microscopes turned on their sides, with the pinhole mounted in the stage and the stages tended to drift.
It's quite possible (as other people have mentioned) to make good quality holograms on a budget, and I even believe the $99 kit (and may have to order it just for fun). The biggest problem with that kit is probably the coherence length of the laser, but a little care can probably mitigate that. That, and keeping the cats out of the kitchen while I do it.
I get to play with expensive optics in fancy labs now, but you can still get bad results if you don't use them carefully. A lot of what they save you is time, and the other thing you get is higher precision, but you don't need super precision for visible holograms--a tenth of a wave or so and you can probably get nice results.