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.
Up until just a few months ago, you needed an expensive laser to make holograms. Not any more. I'm creating holograms using a $7.99 laser pointer. This section of my website will keep you up to date on my progress as I experiment with, and develop, more advanced creative techniques such as color control and mixing, animation and simple stereograms utilizing the pointer as light source. It will start out as basically a series of dated technical reports as things move forward -- and then that information will be compiled into somewhat of a "coherent" instructional guide. (guide is now available here)
For additional information, please check my Holography Link Page at this site, and/or tune into my weekly internet radio talk-show HoloTalk, which will provide updates as part of the broadcasts.
This is a wonderful opportunity, never before available, for artists to explore creative holography. To move into a three-dimensional recording medium, with the ability of color control and mixing -- inexpensively -- should add to that appeal.
For Home-Schoolers, it is a great chance to do exciting science experiments without having to pay for expensive equipment. Making a hologram covers many areas of learning such as optics, the science of light, lasers and how they work, and also gives an outlet for creative expression as well. You can cover a lot of educational ground just in one shot making a hologram.
For schools, this can move holography into classrooms that found themselves not being able to enjoy the discovery of what holography offers with optics and light due to the previous high initial cost and sometimes difficult set-ups. In many instances, it may now move holography from the science classroom into the arts classroom as well. I always like to promote "team" holography in schools, with the art classes supplying the creative input, models and staging and the science classes working out the technical needs of production -- creating communication, team-building and problem-solving skills between two groups that rarely have project interaction.
For amateurs and hobbyists that have been enjoying holography for years -- here's something that's new all over again. The low-cost, higher power diodes may even allow many to move into larger formats -- creating display/exhibit holograms for the first time. Inexpensively.
I was contacted by Steve Michael of Three Dimensional Imagery just before he was to be a guest on HoloTalk, my laser and holography talk show. He wanted to push his date back because he was working on something that would be very exciting to amateurs, hobbyists, students and teachers. Turns out, he managed to create a hologram using a laser pointer (Steve used the Rocket laser pointer from Edmund Scientific in Barrington, NJ). You can find a link to Steve's site on my Link Page, which now contains a special section devoted to laser pointer holography as it grows. Steve Michael's site will also give you a nice background on putting your own working studio together where you can create your own holograms very affordably.
To those of you who
may not be familiar with holography, this news has made the field of
display holography more affordable
for everyone. It had been believed that laser pointers (or diodes to be more exact) did not have enough coherence length to record any depth. You could use one to light up a laser transmission hologram, but you could not use one to create a hologram.
These pages are NOT a guide to making your own holograms. They are the notes of my individual experiments. If you'd like to make your own holograms with a laser pointer, try my Shoebox Holography System, which has a complete guide on how to "do-it-yourself".
My current experiments revolve around taking laser pointer holography a step further -- into making multi-color holograms and other moderately-advanced techniques, such as animation and simple stereograms -- and putting it all together into one inexpensive, easy-to-use system. There is a lot of room for experimentation and discovery, and it is a most exciting time once again in holography. My beginning goal is not to create any breath-taking content, or to get the brightest hologram (that will come later). Right now, I'm more concerned with getting the process to work and then work to improve image quality.
The laser pointer that I am using (shown in photo above, next to a BIC lighter for size comparison) was purchased at a local drug store chain (Eckerd Drugs, owned by JCPenny chain) for $7.99. It is a 3-5mW, 650nm diode. As a stand-alone unit, it operates off of 3 LM-44, 1.5-volt watch-type batteries. It is called the Bullet Beam Laser Pointer and is made by VECTOR Manufacturing, Ltd. The part number on the package is VEC150S. The mailing address for VECTOR is: VECTOR MANUFACTURING, Ltd.; 3003 Greene St.; Hollywood, FL 33020.
For my work, I have it hooked up to a Rectocon power supply -- so I do not have to continue to buy batteries (reported to run 2.5 hours on a set of batteries). This is the same type of power supply that can be purchased at any electronics store and is usually used to power portable walkmans. I have it sending 4.5volts into the diode, and have placed the diode in a small vise grip which is attached to the holography table edge and keeps the pointer stable while also pushing down the "on" button for continuous operation. It has been running fine for several weeks now. In the above photo, you can see that the beam this diode produces is much rounder than the usual pointer beam. WARNING: Diodes are very sensitive to the slightest changes in current/voltage. You can burn a diode out instantly if not careful (and even if you ARE careful). Hook your diode up to a power supply at your own risk. You must also make sure your polarity is correct before applying power -- as many diodes are not polarity protected (fortunately, this model is).
Due to the collimating optics within the diode assembly, I have found that it exhibits more of a "round" beam profile than most pointers. I have noticed though, that beam profile and power output is not consistent throughout the 10 pointers that I purchased (same model). So if you get a chance to "test drive" your pointer before you purchase it, ask the sales clerk to get a few of them for you to look at. This diode is the pick of the batch, and is a real screamer.
The above photos show the beam being passed through a spatial filter (a classic JODON from 1983 -- still a workhorse!). The photo on the left is during adjustment of the x, y, and z micrometer heads. The photo on the right is the final beam profile at fine adjustment. The objective is 10x and the pinhole is 25-micron -- which gives a nice divergence on a 4x8-foot table for a 4x5-inch hologram. A very clean, beautiful 5mW beam spread for $7.99!
The power output, spread and profile quality are very acceptable for holography. Just about what you would expect for your typical 5mW HeNe, which sells for up to $800.00 in some catalogs. It is very clean and even in intensity across the spread of light in all directions. Keep in mind, you do not have to buy an expensive spatial filter to make holograms with pointers -- a $10 expanding lens (try a -12 double-concave lens) will do just fine, if kept in good clean condition.
Keep in mind, however, we still do not know which diodes will work for holograms and which will not. There's plenty of work left to be done.
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Frank DeFreitas Holography