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Toys Science Technology

Making Holograms In The Kitchen 186

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."
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Making Holograms In The Kitchen

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  • by i_want_you_to_throw_ ( 559379 ) on Friday November 12, 2004 @05:32PM (#10802873) Journal
    You can get it from Amazon. It's Shoebox Holography [amazon.com]
  • laser (Score:5, Funny)

    by roman_mir ( 125474 ) on Friday November 12, 2004 @05:33PM (#10802885) Homepage Journal
    The hologram kit costs $99, including the laser, film, and everything else." - what, no shark? it's a bloody rip off!

    • The hologram kit costs $99, including the laser, film, and everything else. - maybe 'everything else' is the shark. I should read more carefully. A shark for $99? Where do I sign up?

  • by Kenja ( 541830 ) on Friday November 12, 2004 @05:33PM (#10802893)
    Gone it seems are the days of making holograms in a basment with a water bed frame filled with sand and a Helium Neon laser scrounged from an old Safeway UPC code reader.

    Ah well.

    • by RobertB-DC ( 622190 ) * on Friday November 12, 2004 @05:45PM (#10803023) Homepage Journal
      Gone it seems are the days of making holograms in a basment with a water bed frame filled with sand and a Helium Neon laser scrounged from an old Safeway UPC code reader.

      You jest, or perhaps you don't? I remember trying to figure out how to set up exactly such an arrangement after visiting one of the first hologram stores in the early '80s. It was in Dallas, in the Quadrangle, I think... I was an early teen, so it wasn't like I drove there myself. It was the coolest freakin' things I'd ever seen -- better than Pac Man.

      Years later, there was an outfit selling holograms at Dallas' West End Marketplace -- and I was able to take my kids to check it out. They thought it was cool, but I don't think they were nearly as bowled over as I was.

      That's why I'm not sure I'll shell out the $99 for this kit for Christmas. I just don't think they'll like it as much as the [Select Kid, Present from WishList where Price < 100] they've been asking for. OTOH, I may send the URL to my wife in case she can't figure out what to get me...
      • That's why I'm not sure I'll shell out the $99 for this kit for Christmas. I just don't think they'll like it as much as the [Select Kid, Present from WishList where Price < 100] they've been asking for.

        Sorry but that's really sad. As a parent you are supposed to (imho, not being a parent myself, and usual disclaimers) be inspiring your children, not letting yourself be brainwashed by commercials or submitting to blackmail by your kids (when under 10 your long term vision isn't quite what it could be).
      • I have a copy of Holography Handbook [amazon.com] which describes building a sandbox. I don't have the book handy right now (packing up to move house), but there's a review on the Amazon page that contains this comment:

        The authors explain, with numerous photos, how to set up a 4'x4'x1' sandbox table, full of 1600 pounds of sand, all "floating" on partially inflated inner tubes for making your own holograms. That way, when the garbage truck goes past the house, no vibrations will disrupt the inertial stability of your o

    • by Jason1729 ( 561790 ) on Friday November 12, 2004 @05:53PM (#10803091)
      This kit uses a laser diode, not a NeNe laser. As far as I know the laser diodes just aren't as good. They also use some sort of instant film, which has its perks; I don't have the time to spend in the darkroom anymore, but I'll believe the quality when I see it, though I am quite interested in seeing it. I wonder if anyone who doesn't have fond memories of making holograms would be at all interested in this kit. It seems to me like more of a nostalgia thing like tbose old video games than a cool new thing.

      Jason
      ProfQuotes [profquotes.com]
      • by sploxx ( 622853 ) on Friday November 12, 2004 @06:09PM (#10803231)
        This kit uses a laser diode, not a NeNe laser. As far as I know the laser diodes just aren't as good.
        Yes, laser diodes have a much shorter coherence length than HeNe's, in the order of 10-20cm whereas a HeNe can easily reach coherence lengths in the tens of kilometers range.
        The coherence length of a light source determines the maximum path length difference between two beams for which you can still get interference.

        It is important for holography since the whole process relies on interfering two beams in the plane of the holographic plate.

        But if you carefully adjust the path lengths of both the object and the reference beam (by putting delay lines into your setup - you can simply build them out of two additional mirrors, for example...), you can surely make holograms out of small objects with a diode laser.
      • Actually a laser diode is more than adequate, often better than HeNe (probably because there's a lot of crappy HeNe tubes going around), but you need to test out the pointers in the store before buying. Boosting the power a bit helps (be *very* careful, it doesn't take much to burn out a diode), as does dropping some cash on a higher powered diode.

        Holoworld [holoworld.com] has a lot of info on laser diodes.

      • True, but without a vibration-dampened optical bench, you won't be making more than reflection holograms with a depth of 2cm tops, so a laser diode is more than adequate.

        Not that it's all that difficult to make such a thing if you have room to do it. I remember there used to be a book about it from the '70s or early '80s by these hippie types, explaining how to build tables like that. Basically it was a big sandbox resting on innertubes of wheelbarrow tires. The optics were mounted on pieces of electrical
      • My impression is these guys were selling a kit based on instant type lithographic film, so buy using normal darkroon developed litho-film, you darkroom time would be about the same as for printing paper (about two min for developing, another two for fixing in dark and rinse under normal light) if memory serves me correctly. I think that given the engery of the light and the sensitivity of the film, your in the dark time for exposure would be a lot longer than for film processing. Given that litho film is av
    • That was a waterbed with a polymer causing the water to "gel" and give slower response to transient noise. The Basment was Alex's and you and I go way back....
    • Coherence Length? (Score:5, Informative)

      by goombah99 ( 560566 ) on Friday November 12, 2004 @06:09PM (#10803232)
      What is the coherence Length of a laser diode? Typically the coherence length of a laser scales with Q of the cavity and the length of the cavity; in effect average round-trip path length inside the laser made by a single photon. This is why large high-q systems like He Ne's worked well for making holograms: they had long coherence lengths.

      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???

      • > 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. Why is that? Isn't the single frequency of the laser also present in normal daylight to enough extent to view the hologram? Or does it have to be a coherent source of the single frequency to view it?
      • IIRC, for single-beam holograms, image depth (how "deep" you can see into a hologram) is generally limited to about less than half of the laser's coherent beam length. One of the best websites there is for laser diode holography [holoworld.com] mentions image depths exceeding 8 inches with a $7.99 laser pointer- meaning that coherent lenght exceeds 16 inches. Mind you, he made sure he got the best pointer of the batch at the store, and also has spatial filter... and this was like 5 or 6 years ago. He also mentions that the
    • Oh, yea, those were the days. At one point I helped a friend set up a cement slab poured onto a set of drums resting on inner tubes, resting on a huge bed of sand. We definitely handled the vibration thing, but the first images were still faint because we bounced the laser too far.

      While this kit may, in fact, have everything you technically need to produce a hologram, I rather doubt that you can produce something beyond curiosity value. Using a 20mw photocopier laser and a rather elaborate setup, we sti
    • I won the regional science fair in 7th grade with my "Holographic Image Quality as a Function of Subject Material." Used stacks of sofa cushions in the basement as a board, and luckily my father worked for a company that supplied the light rail/setup equipment, laser, and silvered mirrors.
  • other uses? (Score:5, Funny)

    by AmigaAvenger ( 210519 ) on Friday November 12, 2004 @05:34PM (#10802903) Journal
    just wait for the porn industry to get ahold of this one! hmnm, wait a minute, seems like porn drives ALOT of industries... nevermind...
  • Leia pic (Score:3, Interesting)

    by Tofino ( 628530 ) on Friday November 12, 2004 @05:36PM (#10802920)
    Any takers on bets for how long it'll take Lucas lawyers to cease-and-desist that Leia framegrab off their front page? :)
  • by drfireman ( 101623 ) <dan@ki3.14159mberg.com minus pi> on Friday November 12, 2004 @05:36PM (#10802924) Homepage
    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.
    • Basically seems to mean the image isn't fixed?
    • by rusty0101 ( 565565 ) on Friday November 12, 2004 @05:55PM (#10803117) Homepage Journal
      I could be wrong, but my experience with a lot of hologram store holograms is that they work best when they are lit by a point type light source. My suspicion is that the result of this procedure is one of that type of hologram, and any 'single point' light source (a flashlight would qualify, but a light bouncing off the celing, florescent tube, or a multi-bulb lamp would not) would work well.

      As I say, I could be wrong.

      -Rusty
      • Errr, you get that wrong.
        This type of hologram (didnt rtfa, but sounds like a amplitude one) needs parallel light in the wavelenght used to create them. So i guess the "special flashlight" is simply a led-light.
    • That's because transmission holograms only work with monochromatic light. So a "special" flashlight would be one with a color filter. Note that it doesn't have to be the same color, either - using a different probe wavelength will rescale the image, but it'll still be visible.
    • by sploxx ( 622853 ) on Friday November 12, 2004 @06:35PM (#10803443)
      There are several types of holograms. The traditional one, AFAIK the first one produced by Gabor, the inventor of holography (BTW... he originally invented holography to make better electron microscopes and not pretty 3D "pictures" :) was a transmission hologram.

      For a transmission type hologram, you split your laser light into two beams, one directly hits the holographic plate and the other one bounces off the object and hits the plate afterwards.
      To reconstruct this type of hologram, you need laser light (or light with similar coherence features).

      The white light hologram (? "Weisslichthologramm" in german) is even simpler to make and can be reconstructed in white light from a point source.
      By positioning the object behind the plate, the part of the beam that is transmitted through the plate hits the object and interferes with the incoming wave in the plate. This type of hologram can be reconstructed in white light because parallel interference stripes form in the plate which act as a colour filter. "The hologram makes the light the way it wants it to be... ;)"
  • by PenchantToLurk ( 694161 ) on Friday November 12, 2004 @05:36PM (#10802925)
    Aah. Can't wait for the amateur holo-porn to emerge. Streaming video surrenders.
    • Can't wait for the amateur holo-porn to emerge.

      Goatse in 3D?! That would give me 3D nightmares instead of the 2D nightmares I am still recovering from.
  • by Nom du Keyboard ( 633989 ) on Friday November 12, 2004 @05:36PM (#10802930)
    A sheet of film and a laser pointer, and before you know it you too can be counterfeiting Microsoft and Master Card logos.
  • Holograms in doom 3 (Score:3, Interesting)

    by freelunch ( 258011 ) on Friday November 12, 2004 @05:36PM (#10802932)
    Doom 3 has some cool rendered [visualwalkthroughs.com] holograms.

    A Princess Leia hologram would have made a nice easter egg.

  • by RollingThunder ( 88952 ) on Friday November 12, 2004 @05:37PM (#10802937)
    ... 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.
  • Edmund Scientific (Score:5, Informative)

    by maynard ( 3337 ) <j.maynard.gelina ... 15926om minus pi> on Friday November 12, 2004 @05:37PM (#10802939) Journal
    Has sold holography kits for years. Currently they have a book Showbox Holography [sciencekit.com] 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
  • Yikes! (Score:3, Funny)

    by PIPBoy3000 ( 619296 ) on Friday November 12, 2004 @05:39PM (#10802952)
    For $100 I sure hope I remember to take the lens cap off.
  • there was... (Score:2, Interesting)

    by Striker770S ( 825292 )
    something on the history channel a few years back about a company that was developing a hologram storage device by waving some sort of wand around in the air and the picture is displayed that way. But the look to it was rediculous, but this is not a completely new idea.
  • Better kits (Score:5, Informative)

    by Anonymous Coward on Friday November 12, 2004 @05:41PM (#10802979)
    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
    • I notice that one of their products says it's "suitable for projection". Can I project a hologram into thin air? How?
    • Given a little knowledge of optics, I don't see any reason these kits can't be used to record white-light viewable rainbow holograms. It would take two pieces of film to create the white-light hologram, but I don't see any physical reason why it couldn't be done.
  • Nothing new (Score:3, Insightful)

    by Jason1729 ( 561790 ) on Friday November 12, 2004 @05:43PM (#10802996)
    Popular Electronics had a great article on making your own holograms in 1992, and it was nothing new then exept that lasers were getting cheap enough to be practical.

    There's even lots of websites now on using a laser pointer to do it, but that doesn't seem to work as well.

    The most difficuilt part of the process is getting the table to be vibration free enough since a montion of less than a wavelength (~0.6 microns) will spoil the hologram.

    Jason
    ProfQuotes [profquotes.com]
    • Re:Nothing new (Score:2, Interesting)

      by Anonymous Coward
      Popular Electronics had a great article on making your own holograms in 1992.

      PE published an earlier cover story on how to build your own HeNe laser in December 1969. The tube could be purchased from Edmund Scientific. For unknown reason, the schematic published in the magazine didn't yield a functioning power supply, but the same components laid out as described in a booklet that accompanied the tube worked fine. The laser was suitable for making transmission holograms, which I did.

      At about the sam

  • does that hologram keep the colors of original object. Or is it whole RED? (as picture on their homepage may indicate)
    • by psyconaut ( 228947 ) on Friday November 12, 2004 @05:48PM (#10803053)
      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
  • $99? how about ~$20! (Score:5, Interesting)

    by k_hokanson ( 80612 ) <hokanson@NosPaM.hotmail.com> on Friday November 12, 2004 @05:44PM (#10803008) Homepage
    instructions here [amasci.com].
  • .. but how do I get princess Leia on my film?

    Rumors allso have it that Padme Amidala is going to wear the buns in the next innstallment.. Perhaps she'll be willing to pose..
  • by DumbSwede ( 521261 ) <slashdotbin@hotmail.com> on Friday November 12, 2004 @05:55PM (#10803121) Homepage Journal
    When working for Wolfram Research many years ago I remember someone working on or with a third party package to generate Holograms from 3 D computer models. It would print out a diffraction pattern, which I believe had to then be photographically reduced and illuminated like any other Hologram. The reduction phase because printers hadn't sufficient resolution (and probably still don't) for small visible wavelengths of light (though if you could "see" in microwaves I guess the original would do just fine).

    A little Googling shows this to be something called a Hadamard Transform. [wolfram.com]
    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.

    • by photonic ( 584757 ) on Friday November 12, 2004 @06:32PM (#10803423)
      I did try this some time ago as a friday afternoon experiment at work (I'm in optics). What you basically do is take some black and white image, take the 2D-fourier and add some random phase noise. This gives you an image that looks just like white noise. Print this with a laser printer on a transparency and hold it in front of an expanded laser beam. Et voila, there's your original image back. There's one caveat: This is essentially a black and white 'amplitude' hologram which contains no phase information like a real hologram. The result is that you always get a ghost image that is point symmetric with the original.

      For more details have a look at this thread [google.com], it refers to a paper that explains the math.
  • by nxtr ( 813179 ) on Friday November 12, 2004 @05:56PM (#10803127)
    I'm always worried about cutting my fingers off when I'm using a regular LASER.
  • by Jason1729 ( 561790 ) on Friday November 12, 2004 @05:57PM (#10803142)
    Hopefully he will read this.

    I love the idea, but 2x3" plates are a bit on the small side, I've always done 4x5s. I sort of lost interest in holography because of lack of time to develop the film, so I might have to pick up this kit.

    My question is do/will you have larger plates, and in the kit, is the laser diode and optics suitable to cover the larger area?

    Jason
    ProfQuotes [profquotes.com]
  • heh, I want one of these.. At least now, I can pretend I have dinner on the table every night!
  • One little catch (Score:2, Insightful)

    by active8or ( 98950 )
    If you look at the bottom of the page, there is a small notice saying:

    Litiholo film makes transmission holograms, viewable with laser or LED light included in kit.

    Kind of spoils the fun, I think. Small type usually does.

    Love,
    . K
  • Misleadingness (Score:2, Interesting)

    by Deorus ( 811828 )
    Ok, this may sound rather lame for those of you who understand what this is all about, but I would like to know anyway: What kind of hologram are we talking about here? Is it really possible to project a tridimensional image in the space? If so, could someone explain me the science behind that?

    I am sorry once again for asking all these questions, but I've been trying to figure it by myself and unfortunately never found anything conclusive.

    Thanks in advance.
  • ECH (Score:5, Funny)

    by ValourX ( 677178 ) on Friday November 12, 2004 @06:38PM (#10803464) Homepage
    "What is the nature of your culinary emergency?"
  • by eric434 ( 161022 ) * on Friday November 12, 2004 @06:51PM (#10803549) Homepage
    We've been discussing [holographyforum.org] 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.
  • by pongo000 ( 97357 ) on Friday November 12, 2004 @07:05PM (#10803649)
    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...
  • Hand-drawn holograms (Score:4, Interesting)

    by William Tanksley ( 1752 ) on Friday November 12, 2004 @07:08PM (#10803669)
    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 [amasci.com].

    -Billy
    • I like the story about how the idea was formed. A guy looked at a just-waxed car and saw that some of the shiny archs looked deeper than the surface of the car. I have seen this effect also in car scratches. Being an amature artist, he realized that the nature of the arcs created an artificial parallax. Parallax is the triangulation that humans use to perceive depth. Thus, he perfected a similar technique to control the positioning of the archs to make planned 3D imaged. He used everyday observations to inv
      • He wasn't the first to make holograms by scribing them. Ruling engines for making diffraction gratings (which ARE holograms) have been around for a century. Nowadays, many diffraction gratings are made holographically, because holographic gratings are more precise and cheaper and easier to make.
  • Where's the @#$% screenshots man??

    :P
  • How much easier is this going to be to make convincing fake IDs? In college I had a nice little hobby of supplying...ah...replacement IDs for friends from states that still used laminated IDs (this was a while back). When I stopped making them, practically every state except NJ, Maine, and Indiana went to credit card style plastic blanks. For a pretty dime you could buy printers that would print on those plastic blanks, but the big issue was you still needed a convincing hologram.

    So assuming you have acce

  • Optics bench (Score:4, Interesting)

    by delibes ( 303485 ) on Friday November 12, 2004 @07:32PM (#10803808)
    I did this in high school. We didn't have a nice optics bench that could prevent vibrations, so the solution was a paving slab resting on a partially inflated bicycle inner tube, and a sign in the corridor to tell people to trend lightly and not slam the door.

    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.

    • Fixing the film didn't seem to work well though - the holograms tended to start fading or something after a few days.

      Possibly something to do with the film. I have a hologram I made when I was a kid (about 15 years ago) at a Uni open day and it still looked ok last time I looked at it not that long ago. Done on car inner tubes, similar to your set-up, can't remember the laser type. It's not done in any schools in the UK afaik. The idea is to NOT make science interesting (just in case someone considers mak
      • Aren't all vehicle tires tubeless nowadays? I recall seeing car tire tubes as floats in pools and lakes, but that was many years (decades) ago. There are mountain bike inner tubes, but they're barely big enough for a turntable plinth. Is there a source for "NOS car inner tubes?"

        HE-NE lasers are much more available than decades ago, but some things are HARDER to find...
  • by sakusha ( 441986 ) on Friday November 12, 2004 @07:43PM (#10803874)
    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.
    • I *have* made holograms without an elaborate antivibration table. Yes, the quality suffers, and you're going to have a lot more duds, but it's certainly possible.
    • by bitingduck ( 810730 ) on Friday November 12, 2004 @10:43PM (#10804925) Homepage
      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.
    • I was wondering when someone was going to address the issue of the mechanical stability required for interferometry (of which holography is a special case). Those requirements can be relaxed if you shorten the exposure times (which generally means increasing the power of the light source, for example by using a pulsed laser), but that does not apply to this kit (which essentially uses a laser pointer as the light source).
      • Yep, stability is not to be underestimated. I'll tell you the coolest holographic interferometry experiment I saw in our laser lab, something that could not be achieved without extremely stable optical tables.
        Neurosurgeons at our local hospital noted a series of inexplicable cases, the patients had all been in minor car crashes, and hit their cheekbones on the steering wheel (this was before the days of air bags). They got minor fractures of their cheekbones, which generally heals with time, so they'd get d
  • This is an open letter to the submitter Paul from the company that sells the product plugged in this slashvertisement.

    Dear Paul,

    I was once again annoyed to see my beloved Slashdot plugged by yet another slashvertisement. Here's a lesson in PR from someone in the industry: It would have been more effective and less annoying if you had just given us the kitchen science and then linked to your site instead of using the summary to plug your product.

    Because of the way you wrote it, you are now getting negative

  • For those who haven't seen it yet...one of the b3ta award winners last year [limpfish.com]. Goodness knows how long it took to do.
  • And holographs, a damn fine way to carry a sentimental reminder and material for knocking one off all in a days work.

    I think these shoudl be mandatory for passports, and i am applying for a job at the passport office in case they do!

    Sorry I just wanted to see a message with 'female genetalia' modded as +5 insightful ! :-)

    Seriously, holographing boobs is mans greatest achivement!

I bet the human brain is a kludge. -- Marvin Minsky

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