Any tips for knife-edging dual 445's...?

[planters]

I am looking at mounting the prism pair and see two methods in this thread. I want to avoid over-engineering while building a good, stable and easy to dial in mount. I could any advice on the merits and tricks.

[laserkits]

Here is my setup. Wave Plate and PBX before the Prism Pair. The trick is setting the Prism Pair at a pretty extreme angle which is well past Brewsters Angle, which results in high losses but a well corrected beam. There is so much bloody power who cares about the losses... I'm getting 1.4 Watts at 1 amp. The beam is 8mm at 30 feet.

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[CDBEAM]

Mr.P....If you are asking on how to mount a pair of A-Prisms...

This is how I have done it...the anamorphic prisms are positioned and mounted/clamped with two (2) acrylic plates which are joined with four 6-32 allen head bolts. A 2mm rubber grommet is placed atop each prism to cushion the prism from unequal downward pressure ( Small black circle ). Basically...one is making a sandwhich !!! When the top plate bolts are tightened...the grommet compresses and clamps the prism into position. Thus...adjustments are always doable down the line. There are four (4) additional mount holes in each plate which provide for securing the entire module to your optical platform.

As to what angle to position the first prism....Brewster ( About 57 Degree ) or more severe as mentioned by LK....well....we are " Between the Devil and the Deep Blue Sea " in this selection !!! At the Brewster angle....minimum transmission loss....BUT...Not maximum beam correction....a more severe incidence angle....more beam correction...but more transmission loss.

Actually....now that I have been experimenting with the Drlava Cylinderical lens set up...with the ultra low transmission loss ( about 3%) with red LD's...I am going to experiment with the
C-Lenses and the 445LD... Perhaps that will also be a better way to go than prisms. I hate " waste " beams generated by the prism set up....well....they are a waste !!!!

Likely others have already done experiments....but I have not seen any posts on this topic. Seems as though everyone ( including me ) have settled on prisms as the #1 method for 445LD beam correction. Perhaps the Good Doctor was WAY ahead of the curve.... Anyone else have improved results with C-Lenses on the 445 ??? Sorry if I did a small thread jack !!!

BEAM

[planters]

CDBEAM,
Thanks for the advise and this how I will go. Incidentally, did you machine the hard spacing between the plates for zero clearance and then with the pads just back off slightly on the retaining screws? I am expanding six 445 diodes at once and will be limited by the prism's clear aperture to slightly less than a 2:1 expansion. That's OK as that in turn is the max my scanner will handle. The problem with the cylinders is that only one of the diode beams can be on axis at a time and the others that are off axis will suffer from progressively greater and greater coma the farther they are off axis. So, to minimize this you can correct two independently and then PBS, but then beyond this you will have to correct and then knife edge or have to accept this aberration. This can get pricy.

[planters]

Laserkits,
I am assuming that you glued the pair down and this is tempting (so simple), but how time consuming was the alignment process. Was this easy; as in align the diodes to the smallest far field spot then insert the prisms and move one or both/back and forth a little? Any special order as you dial it in?

[CDBEAM]

Eric, I just used two pcs of Acrylic plate stock...at about 13mm thickness. The reason for such thickness is ridigity. I have used less thick stock....but have seen some flexing with thinner material....and clear acrylic allows for viewing of prism position. Simple !! I takes a steady hand to lower the top piece vertically....and to not disturbe the prism position....but B4 full clamp force is applied....reposition can be done !

BEAM