LASER POINTER / SEMICONDUCTOR LASER HOLOGRAPHY
by Frank DeFreitas Holography Studio
Creative Holography Using
My magical journey of making
Inexpensive Laser Pointers
holograms with a $7.99 laser pointer
and inexpensive laser diodes.
First Workshop Hologram 1/18/99
(NOTE: Holograms are not 3-dimensional on your computer monitor).
The above hologram is the first student laser pointer hologram created in my lab during a workshop (it is of an antique miniature brass urn). A group of 7 people from the New York area came in to learn about how to make holograms with a laser pointer. It was created by Michael, and his sister Brittany did the processing (and also made a hologram). In all, 5 students made holograms in about 3 hours. Finally, it feels good to know that I'm not dreaming about all this, and having a group of people create their own holograms confirms that it indeed works. This hologram was shot under conditions that would challenge the best set-ups: 8 people (including myself) in the lab, middle of the day downtown traffic, and quick processing.
Shameless, non-solicited self-promotion:
(Email received earlier tonight from one of the Moms):
We just had to thank you again. We had such a wonderful time. The kids said
you were "so nice" and really knew how to explain things so they could
Michael said, "When are we going back again?" In the next few days, they
will be e-mailing you. On the way home, they thought of more things they
wished they would have asked you. We'll let them ask you themselves.
It really was great, and it was well worth the trip. We'll be in touch."
It is a 4 x 5 hologram. No triethanolomine treatment, so the color (pretty close in the photo to the actual color) has not been modified. Exposure was 6-seconds on an AGFA 8E75HD plate, processing was PyroChrome. Just pop the plate in the holder, settle (as much as possible with a crowd) and shoot. Settling time was only 10 seconds before the exposure. We had to shoot a lot of holograms in a short amount of time, so it was good to see whether quality would hold up under pressure.
Overall, not an astonishingly bright hologram (not dim either, let's say: nice), but a very clear, deep image. You can look down into the urn as you tilt the hologram. Of course, I forgot to get a picture of it looking down into the urn to show you.
In any case, just wanted to pop in with a quick report on this -- especially since so much time and care was put into the previous test holograms. It's not that difficult getting good results under carefully controlled conditions, but quality can drop quickly and dramtically anytime variables come into play.
There was a time when all 8 of us were standing around the holography table and I could feel the body heat. I knew this would not have the dramatic effect it would have if we were shooting split beams (beam path length micro-changes due to thermal conditions around the table). Another example where single-beam saved the day.
I have a10mW, 640nm diode module ordered. It runs on 3volts, so I'm going to hook it up to two AA batteries at first. I don't think I'll get brave enough to try the power supply, but who knows.
I paid $185 for the module, which contains high-quality, focusable collimating optics and the power chip in a brass housing. It has two rat-tails coming out of the housing for power. I just got a "famous" science catalog in the mail yesterday and they have their 10mW HeNe lasers selling for $1,280.00 for 1999 -- so $185 isn't too bad. (The 5mW HeNe's have jumped in price to $880 now -- I'll stick with my $7.99 pointer, thank you). I could have saved money on the 10mW by buying the components separately (almost half) and soldering the diode to the chip, but I'm not that comfortable with it yet. Maybe with the 35mW Hitachi.
Check back for updates. And don't forget to visit Steve Michael's site (listed at the top of the link page) as he's doing some great work, of which I will update on this upcoming week's HoloTalk (1/25/99). You'll also find photos and diagrams of how to set up to do your own laser pointer work at his site as well.
If you manage to do a laser pointer hologram, please let me know. I'm going to put up a page with holograms that others have created. Meanwhile, I'll continue to push this forward -- hoping not to give the HeNe laser sales people a heart-attack along the way.
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Frank DeFreitas Holography