Question about anamorphic prisms

**absolom7691** · 05-02-2011, 02:44

Very nice! What size pinhole were you using?

**kitatit** · 05-02-2011, 03:02

Originally Posted by dnar

Hi Kit, here is a shot of the final beam after pinhole. Taken at 500mW, single diode with Simon's prisms. The daytime photo with the green shows the beam is tight, the 532nm is the CNI 1.5mrad.

Attachment 24809 Attachment 24810

Niiiiiiice

wow thats great! that opens up a few possibilities. Thanks for the pics.

Time spent in your upstairs bat cave is clearly yielding results!

**dnar** · 05-02-2011, 04:38

Originally Posted by absolom7691

Very nice! What size pinhole were you using?

Much larger than you would think. I'll measure it and get back to you.

Originally Posted by kitatit

Niiiiiiice

wow thats great! that opens up a few possibilities. Thanks for the pics.

Time spent in your upstairs bat cave is clearly yielding results!

Slowly. This projector build is one year in and counting!!!!

You now have a set of Simons prisms, they are what I am using. Prisms and pinhole. No moving parts lol.

Here is a shot of the pinhole blue and my CNI green, quad red after a bounce mirror (10 meters?). The 1.5mrad CNI green is the fattest beam!!!

DSC00127.jpg

**absolom7691** · 05-02-2011, 12:50

Here is a shot of the pinhole blue and my CNI green, quad red after a bounce mirror (10 meters?). The 1.5mrad CNI green is the fattest beam!!!

This is awesome. This is exactly what I am looking for. This should really help with graphics!

**absolom7691** · 05-06-2011, 17:49

Just got my prism pair today. I am wondering if some of these 445's have better beam profiles than others. I just popped another 445 into a housing and I am using a generic glass collimator and it has a pretty tight beam. I am going to throw the optics on to clean up the FA but this looks really damn good.

dnar, were you able to measure your pinhole? I am curious to try that out. I have a pretty good beam already, but if I can round it up, it will be on par with my 640 and 532.

**dnar** · 05-06-2011, 21:35

Originally Posted by absolom7691

Just got my prism pair today. I am wondering if some of these 445's have better beam profiles than others. I just popped another 445 into a housing and I am using a generic glass collimator and it has a pretty tight beam. I am going to throw the optics on to clean up the FA but this looks really damn good.

dnar, were you able to measure your pinhole? I am curious to try that out. I have a pretty good beam already, but if I can round it up, it will be on par with my 640 and 532.

Yeah buddy, just measured it for you. 3.4mm. It really just clips the corners of the beam without much loss at all.

**absolom7691** · 05-06-2011, 21:46

Awesome! Thanks! I am going to give this a try.

**dnar** · 05-06-2011, 21:51

Originally Posted by absolom7691

Awesome! Thanks! I am going to give this a try.

Cool. Depending on YOUR beam profile and size you might want to experiment with the hole size.

Here is a pic of it in action, I am using the B&K housing which came with a very small exit aperture, I slowly drilled it out in increasing sizes until I got the result I was after.

**absolom7691** · 05-06-2011, 22:04

Very nice indeed! I still need to get everything mounted proper. Right now, my diode/housing is mounted to a bare heatsink and my prisms are just sitting on it. I need to do some fabrication to make it an actual laser head! I have a few pieces of black anodized angle. I'll grab one of those and start drilling it out for the best beam. This is great though, your work here is going to make 445 a more viable choice for graphics. You should probably post your own thread on this with your findings to "show us all the light!"

**allthatwhichis** · 05-06-2011, 22:42

What if you used two prism sets, but put them both at different "polarities"; have one set 90 degrees off axis from the other set?

**LaNeK779** · 05-07-2011, 06:25

Originally Posted by allthatwhichis

What if you used two prism sets, but put them both at different "polarities"; have one set 90 degrees off axis from the other set?

someone has already done this and posted pics over here, but i can't seem to find it at the moment.... and i also can't seem to remember who it was.....

**dnar** · 05-07-2011, 06:28

It was Smog, here is his thread.

http://www.photonlexicon.com/forums/...morphic+prisms

**absolom7691** · 05-08-2011, 21:54

dnar, you are my hero. Finally got my prism assmebly made and along with my pinhole set-up. Nothing is mounted in a housing yet, but I did manage to capture a few pics to show this in use.

Please note, my camera has a very hard time with this wavelength. I think most CCDs do. Though it may look violet with a lot of beam trash, there actually is very very little. Most of the "trash" is caused by my camera. Anyway, these were captured F16 (to reduce glare) at about 1/15 secs and the scan angle is very small <10 degrees (hence the fat beams). The blue is on par or slightly better than with my green. This setup is very suitable for graphics. I think the only thing that is going to show is when it is mixed with 640 red. Because the red beam is so small in comparison, I have viloet with a blue halo. I have the same issue with green/red, but because of green's brightness, I can't see it.

IMG_3113.JPG IMG_3111.JPG IMG_3115.JPG IMG_3112.JPG

**dnar** · 05-08-2011, 21:57

Nice. be sure to post pics of the final setup!

Originally Posted by absolom7691

dnar, you are my hero. Finally got my prism assmebly made and along with my pinhole set-up. Nothing is mounted in a housing yet, but I did manage to capture a few pics to show this in use.

Please note, my camera has a very hard time with this wavelength. I think most CCDs do. Though it may look violet with a lot of beam trash, there actually is very very little. Most of the "trash" is caused by my camera. Anyway, these were captured F16 (to reduce glare) at about 1/15 secs and the scan angle is very small <10 degrees (hence the fat beams). The blue is on par or slightly better than with my green. This setup is very suitable for graphics. I think the only thing that is going to show is when it is mixed with 640 red. Because the red beam is so small in comparison, I have viloet with a blue halo. I have the same issue with green/red, but because of green's brightness, I can't see it.

IMG_3113.JPG IMG_3111.JPG IMG_3115.JPG IMG_3112.JPG

**allthatwhichis** · 05-08-2011, 22:49

Originally Posted by dnar

It was Smog, here is his thread.

http://www.photonlexicon.com/forums/...morphic+prisms

It looks to me as if those prime were set up 180 degrees off axis instead of 90 degrees.

I might have missed the other position; correct me if I am wrong.

**CDBEAM** · 05-08-2011, 23:09

Pics/drawing below are associated with work ongoing with the ZQuad ( four 445LD combined ). This is how the anamorphic prisms will be positioned and mounted within the ZQuad. Two acrylic plates 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 Anamorphic Prism Module Pic 1.jpg down the line. There are four more holes in each plate which provide for mounting the entire module to your optical platform.

This is one way to mount Anamprphic Prism Module Pic 2.jpg the prisms and have adjustabillity. Thought this might be helpful.

Finally, a worthwile contribution from Terrawatt Labs !!

CDBEAM ,,,and TerrawattZod Quad Anamorphic Prism Pair v 1.3.JPG

**swamidog** · 09-28-2011, 10:03

you'll go from this "---" to this "-", but what you really want is this: "*".

Originally Posted by absolom7691

I have seen a bunch of threads talking about how the anamorphic prisms can clean up the beam a little for 445's. What kind of "clean" are we talking here? I am using one of the aixiz collimators right now, and that has helped a little. Basically, will a pair of prisms get me an "adequate" beam profile for graphics? I understand that, at best, I will be getting a square beam, but how tight will the dot be? Right now, anything has got to be better than the "|" shape I am getting.

**CDBEAM** · 09-28-2011, 10:23

The GB Barr coated anamorphic prisms from p1t8ull deliver a 14mm square at 40 feet ( Olike collaminator ). That is .738 mRad...No problem.
No line...a square. Fine for beam shown and graphics.
CDBEAM

**planters** · 10-11-2011, 13:27

Can anyone direct me to a simple step by step for adjusting a prism pair? Say you have a stack of 445 colimnated beams like " lll " and you wished to expand the stack from 3mm to 6mm. How do you set the first prism angle and then the second? Is there any optimization other than two parallel, but offset beams?
Thanks

**polishedball** · 10-11-2011, 18:00

http://www.photonlexicon.com/forums/...4&d=1283181999

**planters** · 10-12-2011, 10:03

Thanks,
Can you tell me what the numbers printed next to the diagrams mean and if each diagram represents a different magnification? Also, if the angles are less than perfect what do you see and what do you adjust?

**Xytrell** · 10-12-2011, 16:07

The numbers are the angle of incidence. If you're off, the magnification will be either more or less. It's not crucial, really. In theory, Brewster's angle will offer lowest loss (third option)

**planters** · 10-13-2011, 09:19

Thanks. That is just what I was looking for.

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