The point of this project was to examine the feasibility of low-cost holography. Can you record viable holograms? How much does it cost? What are the major difficulties?

If you haven't yet, be sure to go look at the images on the Stills page. The daphnia does clearly come into focus, and although I have seen much nicer images generated by the high-level systems in our lab, this is not bad. In the close-up image set as well as the full frame, you can see other objects coming into focus, notably the dust on the front of the test section at around 1mm (full frame) and a small particle to the right of the daphnia at around 3mm.

I was most interested in recording movies of the plankton, however the resolution of movies recorded with this camera was just not good enough. If the lenses were moved in order to magnify the target significantly, it may be possible to get better results. Not being able to remove the camera lens was a major hindrance, because it required another lens to counteract it, made calculating the magnification a tricky proposition, and prevented me from being able to see for certain whether the laser light was collimated, expanding or focusing when it hit the CCD.

The laser pointer itself is the cheapest part of this system- only $10! It has a coherence length sufficient to produce a distinct interference pattern (unlike LEDs), which is what we need for holography. The manufacturer of this specific laser pointer is Lazerpro.

Lenses similar to the expanding and focusing lenses used in this system can be obtained for around $50. The large collimating lens I used is a different matter- it costs hundreds of dollars. This is not a fatal problem however, becuase a smaller diameter lens can be used and the field of view will just be smaller. An optical rail and poles to hold the optical elements could cost another $100 or less.

I used the Fujifilm Finepix S602 because it was available. It sells for around $600 online. It has some very nice features (the SP mode lets you record black and white still images, which saved me the trouble of converting them from RGB later). A removeable-lens digital camera would be ideal, as I mentioned above. A higher resolution movie mode is also very desireable.

Assuming you already have a digital camera or can borrow one, you can build a a laser pointer holography system for $300. This is the major advantage to digital holography- no expensive film and no strange (and sometimes carcinogenic) developing procedures.

When those cell-phone cameras get a little bit better they might even work!