If I'm understanding this right, a “hologram” is an ordinary black and white photograph that has been exposed in an extraordinary way. A normal image is exposed under white light, using a complicated system of lenses to try to make the light rays converge into a coherent image. If I understand correctly, a hologram involves illuminating a scene with two identical laser light sources, and having no lenses at all; the photographic system simply records the interference pattern of the two lasers (which depends on what they're illuminating, and hence records an image).
Now, presumably the size of the interference patterns is comparable to the wavelength of the light involved, which is where I suspect there might be a problem. For example, my camera has a dot-pitch of 5μm (and a Bayer filter). The wavelength of red light is more like 600nm or so, which is quite a bit smaller.
I gather normally they use glass plates coated in photographic emulsion, which presumably has considerably better spatial resolution.
So, in summary, can you make holograms with a DSLR? Has anybody done this? Or is it a fool's errand?
(Of course, assuming you manage to take the picture, printing it may also be... entertaining.)