If you use galvos with overcoated silver mirrors or overcoated aluminum rather then multilayer dielectrics, the amount of polarization rotation vs wavelength is minimal. With either two combined polarized lasers or two scan heads, This makes beautiful stereo images with polarized glasses.
Its even more kick ass if you overlay three-D laser on a 2D or 3D black and white movie. Seen it a few times and loved it, best stereo effect I've ever seen before Avatar. You need the right type of screen or paint on the wall, too, although it need not always be silver paint, some very common matte wall paints using titanium dioxide whites work just fine.
Pangolin's older cards output X and X Prime or a Z voltage for a reason. It is not difficult to compute the second viewpoint in software for X Prime or do it in analog opamps when you have a Z signal. The average distance between eyes is what, six and a half inches?
Like many things you can do it in the Laser Arts, it is a bit more artistic and technical work then most people are willing to put up with in the pursuit of the Almighty Dollar. With modern single mode diodes, it would be a lot easier with their inherent high polarization ratio then in the old days with Ion where you needed expensive broadband waveplates or a really tricky arrangement (For a non-techie) of beamsplitters and mirrors. Galvos are far less expensive now, too, so the idea of six diodes and two scan heads is far cheaper then back in the Dome days. .. Been meaning to get back to it lately, but Running Steve's Senior Care Center for Mom gets in the way of spare time. Even easier now that LH/RH circularly polarized or +45/-45' goggles/glasses are common because of movie theatres.
Don't bother if your using modern dielectric mirrors on your scanners, the changing angle really clobbers the polarization in most cases, resulting in different polarization rotations for each wavelength. . Yes, I know that I can order dielectric coatings that preserve polarization, but the coatings on most galvo mirrors are not the "Special" optimized stack used in lab grade optics or fold mirrors. They might work acceptably at a single wavelength, such as red, for experiments.
That is one of the many historical reasons for the 3D format. Chromadepth is one of the other reasons. I'm not a Chromadepth fan, it used to give me Migrains for some reason, not to mention most of the depth was from the green and yellow Krypton lines, which are now not so common.
The other good reason to bring it back is software UGC now is common vs hardware UGC which is still expensive to do. Much easier now to overlay two scan heads if you know what your doing.
I just remembered I used to work with the Professor who patented the way to make broadband plastic waveplates, so now even those are somewhat inexpensive compared to the 70s.80's 90s precision quartz broadband waveplates which back in the day could be 1000$ each.
With six single mode diodes, that would give you dual 450 mW projectors, one for each polarization. To go any higher in power your back to green only, monochrome only, OPSL or Ion, or seriously expensive real time active polarization rotators.
(PS, it doesn't help that one of the dominate early programmers / show creators in the industry traditionally hated the polarization technique, and that two of the others are / were differently abled and thus cannot see it. I'm not naming names, so don't assume you know whom, either. Yes, I also know there is one inadvertent Cyclops who does support 3D who tilts their head a lot when its running, in an attempt to mentally compute the perspective. )
Steve
Last edited by mixedgas; 05-02-2020 at 11:58.
Qui habet Christos, habet Vitam!
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When I still could have...