Topic: Home made knife edge combiner

[James]

Check this out!

I found a little first surface mirror that was in "ok" condition for an experiment.

I cut a piece of Aluminum to an angle of less than 45 degrees and used J-B Weld Epoxy to glue the mirror to the Aluminum.

It took over night for it to fully harden.

Then I carefully worked the back of the mirror into a flat piece of wet sand paper facing up on a piece of thick plate glass.

The technique is called lapping. It comes from lapidary, the art of cutting and polishing stones.

I started with 180 grit and went through 320, 400, 600, 1000, & 1500. I had some 2000, but I don't have a fresh sheet.

As you can see, glass wet sands very nicely!

Now I guess I can either try this one or make another one!

James. 

[Ignativs]

nice

[James]

If you want to combine the power of two beams, then you would typically use a dichroic beam combining optic. But, that absolutely requires that the beams are of different wavelengths (colors). So what do you do to combine two beams of the same wavelength? Well, in many cases, you will rely on the fact that the beams are strongly polarized and use a polarized beam combining cube. But what do you do to combine two beams that are non-polarized and the same wavelength?

You use a knife edge combiner!

The idea is that one of the beams is aligned to just graze of the edge of the mirror and the other beam is aligned at 90 degrees of the first one to bounce off the surface of the mirror as close to the edge as possible. The beams will never be completely coincident, but that doesn't really matter so much for the DPSS greens, because they have such a small beam profile. You can align them well enough such that the two beams are super close, side-by-side.


http://laserboy.org/forum/index.php?action=dlattach;topic=436.0;attach=2032

James.