in my last post i forgot to say were i was well im in seattle and i am looking for people with the same interest to get together learn from eachother and split the cost of getting the stuff we need to start making holograms the last time i made holograms i waisted 600 dollers on an unstable 20mw tube laser i was 18 at the time and very pissed off. 7 years later today i seen a hologram and cant get that magical picture out of my head.
so email me if you are interested at justingene@aol.com
for the first experiments you don't need expensive things. buy a laser, best for beginners is a HeNe about 6 or 7mW, TEM00, linear polarized (<$100 on eBay). you also need holographic film, high resolution developper (like "Dokumol" from the photo store) and bleach (i got the components in a drug store). and last but not least a lens. it's not important if convex, concave or combinated. pick one from an old cd-rom drive. it's not the best but ok for beginning.
some other things like film holder, tables, water you will find at home
see my first experiments in the gallery on www.hologramm.ch.vu (sorry, german only)
wow you sound like me my first laser was even less than yours it was only 5 miliwatts but i did get holograms with plates but a total bust on the russian film the laser was stable but not the film holders so i got out of it for a while now im back with a vengence i got a argon ion WOW what a beam 520 nm pure green problem now is exposure times at full power its like .5 seconds so i use a few beam spliters to pad down the beam so the exp time goes up im working on a new iso table its gonna be a combo table 10 inches deep 6ftx6ft with a 1/4 steel plate lid that sits on the sand this way i have the best of both worlds mainly because i dont whant sand near my argon this time i got sand in a larger grain not from the beach yes all my other holos where made on daytona beach sand the whole secret is isolation isolation isolation
between the white table and the floor (see my pic) is an air hose to isolate. i have the privilege of a house away from big roads and in the night it's very quiet
I once built a sand table 8' x 5' and put sheet metal over it (mainly so could use mag mounts). A couple od problems I had were that sand still managed to get to the optics since I could not seal the edges - ie there was an edge of about 1/4" between the table walls and the metal sheet. I had to wash the metal surface daily to get rid of sand on the surface so that it didn't get under the mag mounts and cause wobble. One mysterious effect I had was that the sand started sloping. After a while the sand built up on one end or the other of the table and there was a distinct slope to the metal.
This table was built with breeze blocks, then a layer of plywood, 8 inner tubes, another layer of plywood, some carpeting and finally the sand box (15" x 8' x 5'). When an inner tube started deflating, I had to shovel 60 cu ft of sand (which weighs a lot, believe me!) onto the floor, dismantle the entire tabe, re-inflate inner tubes and re-mantle (re-mantle???) the entire table. Then an engineering friend simply connected all the nozzles of the tubes together and had one nozzle stick out. This way, if one copllapsed the others filled it out and I got an average effect. If this average was too low, I used a bicycle pump. Clever, these engineers!
I had a similar table once set up in a second story apartment. Only instead of sand, I used low expansion refractory glass bricks. PPG sells glass foam bricks for lining ovens, and a special high silica cement for putting them together. I made a 4' x 4' x 3" thick layer of foamed glass out of it and then placed a steel plate onto felt on top of that. The rest of the table was similar except I used Goodyear pneumatics instead of inner tubes on the first stage and bicycle inner tubes connected with tygon tubing on the top stage.
A note: Colin pointed out that by keeping the tubes separated, one might adjust levels and individually damp as appropriate. The remote filler tube concept is a darn good one, to access air pressure and all... but...
To the Congregation: I have described several active vibration damper schemes here and on the Yahoo site... os far no one has reported using one?? Its easy and can be implemented with nothing more then wood shop skills using woofer speakers as pistons and a hanging stick in an optoelectronic collar as a kind of 'gravity joystick'. The stick or string or rod or bobbin or....hangs 'down' and the differential signals from the collar, controls the positioning of the low frequency woofer speakers to change the air pressure in the table top bladders (inner tubes, hot water bottles, multilayer mylar balloons, etc.). If wished, each bladder can have an additional optoreflector looking up from its perch to the suspended table above it, to initially set the air pressure and thus the height, calibrated for a 'medium' value. The speaker chambers modulate that 'medium' pressure, to lock out external noise transients. The system can as a convenience, lower and re-raise itself to 'operational suspension' on command so that while working on the setup, the table is down and stable, and on completion the table is raised, set to calibrated height and auto locked.... Well, anyway........
