Need "Reverse" PBS for 20W "laser tank gun" prototype - do they exist?

[Light superglue]

Several months I have been disassembling, reassembling this setup, replacing and rotating LDs...

The LPF site has changed a lot i between... I cannot even expand my own posted pictures if not logged in...but this is not a big deal.

Finally put all parts back together. Now the 4 LDs combined here are 06, 08 and two 07s.
Two of four LDs (where space allowed it) are now equipped with G-2 lens, two others where was no place for G-2 keep Gballs.

What was really difficult is to make beams fall at Blue-blue dichro at recommended 45º angle.
If at low power this seemed fine (not much light loss), at 4.5A a lot of light goes by side - you see the huge expanded spot on the white plate (pic.3). Especially from 07s - there was amost no output increase into the main beam passing from 3.5 to 4.5A - all went to the side.

So, finally I could not reach the expected 20W but 16W are there in the main beam.
So the output of each LD alone mesured through the whole optical trail:

At 2.3A (16.5V) 2.85 2.89 2.02 2.03 total 9.79W, efficiency 26%

At 3.5A (17.3V) 4.22 4.18 2.67 2.90 total 13.97W, efficiency 23%

At 4.5A (18.2V) 4.98 5.45 2.77 3.05 total 16.25W, efficiency 20%

Anyway being focused with Sanwu expander at 5m the combined beam already burns the white wall paint at 2.3A current (pic. 2)
Then at 4.5A the second spot beside the first one was quickly growing (pic.4 & 5). Pic.6 is the resulted wall to compare spots at 2.3 and 4.5A
The Al baseplate also got warm as it should at 82W input.

I think I had to put sacrificing PS or PVC sheets on the wall - all of it is in black spots now!

 

[paul1598419]

I noticed you used the PCV lenses from cyl lens pairs, but then added both to one PCX lens. Seems like that would be difficult to line up properly. As my old calculus prof used to say, "nothing succeeds like success."

 

[Light superglue]

Yes, it was a plan to minimize the trail footprint to fit on the 120x70 mm baseplate.
Now I see that it was not a perfect idea - even when the centers of expanding beams fall on Dichro at 45º, the outer parts do not seem to...

 

[Pelagius]

Very interesting project! Did you lose power earlier through destructive interference? Anyway- fun project. You might need to repaint your wall. Luckily it was not a dark color.