After the mixed success of my first RYG laser, I decided it was time to try to make a full color RGB laser. There were 2 main problems that I ran into in the process: finding a blue laser for a reasonable price (I spent all of $0 on the RYG laser), and keeping all of the optics aligned well enough (a big problem with the previous revision). For more information on the creation process of this and later revisions, check out the forum post I made on 4hv.org.
Luckily, the blue laser issue solved itself, because right at the time I was working on this project Blu-ray and HD-DVD were the hot new thing, and every player for these disks has buried inside a ~5mW 405nm laser diode. A little searching on eBay later and I found an auction for the optics deck out of a ps3, which I won and dismantled to extract the laser diode.
With that problem out of the way all that was needed was a more stable method of mounting the components that wouldn't let them drift around, and after some experimenting I ended up using a technique I found in some commercial laser products, where the optics were bonded to glass blocks, which are then glued to a rigid base. So I dug some glass windows out of the optics junk box, and ended up using 'gap filling' CA glue (ie, really thick superglue) and an accelerator product to help it cure.
That taken care of, I tried to glue it all up into a finished laser. I started out by laying out the beam path to get a feel for where everything would go, and then gluing down the red laser:
Then I added in the blue and green lasers:
(the 2nd picture is actually of an older mounting design, but you get the point)
This all worked reasonably well, and I had a very nice white laser beam!
(the white balance is off in the pictures because my camera does not pick up green as well as my eye does)
And I could even change its color by turning the lasers on/off
This all worked very well, until I tried to take the plate off of my optics bench. As soon as I took the clamp holding it down off, I could see the beams drift out of alignment again as my aluminium plate flexed slightly. Back to the drawing board; again.
This lead to the creation of RGB laser III, which should solve the flexing problem, and look a lot cleaner.