I'm designing a laser to shine a dot at a breath-taking 68 kilometers over a frozen lake in Hungary.
I have experience working with 445nm diodes, my current working laser uses an m140 diode, but I am hoping to engineer a more powerful laser using either singular nubm44's or multiple nubm44's using knife edge array configuration.
I have noticed that almost all blue solid state laser diodes suffer from fast axis dispersion, which at 68 km would likely be hundreds or thousands of meters wide, which is no good for the task at hand.
Here is a photo of my current laser:
Here's a video of the problem:
I have come across a special type of lens known as the FAC08-600
I've been told that FAC lenses have not been used to date to correct the fast axis of neither the nubm44 nor the m140 laser diodes.
I can already squish the beam into this rectangle using the G2 lens, however I feel the FAC lens might be able to squish the fast axis into a tiny square or a "dot" suitable for long range work. To my knowledge there is not an adapter for this, so I begun work on a custom, adjustable housing for a FAC lens to a laser pointer. My intention is to use grub screws to correct vertical alignment and a pair of worm-wheel/worm-gear combinations for micrometer adjustments to the lens plate.
The design is still a work in progress, I was looking for cheaper sources of brass wormwheel gears, but I feel there may be chatter/rattle. I figured this is most likely the best way to align the lens to within micrometers or precision. I have begun work on the roll design for the lens, no work done to the pitch, do you guys think I should do a yaw also?
The plan is to machine the DTR laser shop copper 32mm housing so that the entire assembly can screw-thread onto the laser module housing and can use this to adjust distance from the FAC lens to the G2 lens. meanwhile using the grub screw to align the FAC lens vertically and the pair, possibly trio of wormwheels for roll, pitch and possibly also yaw of the lens.
Should a single nubm44 laser diode be of insufficient power I am considering using 4 of them in a knife edge array also into the same design.
The holders of the lens are also designed to dissipate heat.
If you guys think this has a chance in hell of achieving what I think it will please say so.
I know this design looks and sounds crazy so I'm all ears to your input.
Thank you in advance.