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Question About Corrective Optics

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So I've read quite a bit about corrective optics and they seem to be the golden solution (for now at least) to horrible divergence in high powered lasers, but why aren't they more popular/more commonly used?

I was reading this thread in particular about a guy who used corrective optics to make his NUBM44 laser have an insane divergence of .35mrad with a beam diameter of 6mm. The dot at 10m away was only 1cm long. This is a quote from that thread that the guy stated after finishing this project,"I feel like this is it now. I never had a laser with below 0.9mRad divergence, and now, ironically, it is coming out of the most diverging and the most powerful diode we have for this hobby. Its amazing." So again, why don't more people do this with the NUBM44s and other high powered diodes???
 

ElectricPlasma

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My guess is price. The optics can be pricey, up to 100$/pair and higher. Also the optics don't fit in some builds, they've got an awkward shape.
 

Sta

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Because it is very, very difficult to align them properly, and makes portability difficult. If they are aligned wrong, or the distance is not exact, your beam will be worse than it was before correction.
 
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That ones DTR recommended for me are these. Only $60 for the two lens and $75 for all the parts needed....thats not bad at all considering how much they will do for your laser....
 
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But how much time does it really take? I don't understand how its just not worth it for people to make their divergence and beam sooooo much better
 

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It is a matter of accuracy, not time. If you misalign the optics you will have a bad problem. Not to mention that it will make it very difficult to make it portable. If you want a lab setup, this is fine, but you will have to build your own mounts if you want it to be anywhere close to portable.
 
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I thought you didn't build lasers, or hadn't done it yet? It will be fairly hard to make a portable M44 w/ corrective optics without good machining or decent macguyver mechanical skills. Not to mention have to be able to build the laser before the corrective optics, then align it all.

If you pay someone to build this... it's gonna hurt your bank account.

Cypreus IIIB is probably what your referring to, and that build is godlike and you won't see many like it. Lots of time, and planning, then machining went into that build. Ask him, his post is here somewhere.
 
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Hmm ok maybe I don't understand how hard it is to align then. I though you would just have to move them closer or further apart until the dot is as round as you can get it (there's obviously more to it than just that, but I didn't think it would be a super hard thing to do). And as far as portability goes, it seems if you just glued them in place they would stay their and you can move the laser all around and they wouldn't fall all the mount or anything. Have you tried doing it before?
 

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Hmm ok maybe I don't understand how hard it is to align then. I though you would just have to move them closer or further apart until the dot is as round as you can get it (there's obviously more to it than just that, but I didn't think it would be a super hard thing to do). And as far as portability goes, it seems if you just glued them in place they would stay their and you can move the laser all around and they wouldn't fall all the mount or anything. Have you tried doing it before?

You haven't considered rotation. If they aren't exactly on the fast axis of the diode, the divergence get worse. Remember that multimode diodes have bar-like output.

And gluing things to lasers is typically a bad idea. If it gets hit by anything, it will break off, or become misaligned.
 
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I thought you didn't build lasers, or hadn't done it yet? It will be fairly hard to make a portable M44 w/ corrective optics without good machining or decent macguyver mechanical skills. Not to mention have to be able to build the laser before the corrective optics, then align it all.

If you pay someone to build this... it's gonna hurt your bank account.

Cypreus IIIB is probably what your referring to, and that build is godlike and you won't see many like it. Lots of time, and planning, then machining went into that build. Ask him, his post is here somewhere.
No I don't build my own lasers, but as you may know I'm looking to get a laser with the NUBM44, NUBM07E, and/or NDG7475 and I'm probably going to end up paying an experienced professional to build one for me. Before I go ahead and pay someone to build me one though, I wanted to do research into how to fix that horrible divergence and it SEEMED that corrective optics did an amazing job at fixing that issue, but I guess they are super hard to align and easily get moved in portable lasers. Depending on how much extra $$ its going to be, I may or may not still go down that route. Some day I think I might build my own lasers, but for now I'd much rather have an experienced hobbyist do a build for me.
 
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I meant glued onto the mount, not the inside of the laser, but I trust you since you' seem to be pretty active on this forum.
 
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ElectricPlasma

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Aligning shouldn't be too difficult, but it's pretty hard to do if you don't have a mount for them. There are these brass machined mounts I've seen around the internet for them and they make it a lot easier as they have pre-made seems to place the lenses.

To get the diode itself aligned to be perpendicular to the lenses I would check out the 12mm XYZ mounts DTR has on his site, just make sure the output is straight and flat as possible. Using a level just like you would be leveling a piece of wood is a perfect way to do it. Good luck getting that kinda result in a handheld though, but it still is possible.
 

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Aligning shouldn't be too difficult, but it's pretty hard to do if you don't have a mount for them. There are these brass machined mounts I've seen around the internet for them and they make it a lot easier as they have pre-made seems to place the lenses.

To get the diode itself aligned to be perpendicular to the lenses I would check out the 12mm XYZ mounts DTR has on his site, just make sure the output is straight and flat as possible. Using a level just like you would be leveling a piece of wood is a perfect way to do it. Good luck getting that kinda result in a handheld though, but it still is possible.
It is definitely possible, but I would not recommend it to a beginner. You should learn to walk before you run!
 
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Ha again, I'm not talking about doing this myself. I'll be purchasing a prebuiilt for my first high powered blue and green lasers (NUBM07E & NDG7475) and if I'm going to be spending $300-$500, I want it to have as good of divergence as possible. It seems a bit ridiculous to spend that kind of money on a laser and get something with absolute horrid divergence and at 10m the "dot" is already a long, thin line. Seeing how much of a massive difference corrective optics can make, I'm very interested in them now. In all honesty, having a laser that outputs a flat line dot on anything more that 10 feet away would annoy me to the point where I wouldn't even enjoy using it.
 
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No I don't build my own lasers, but as you may know I'm looking to get a laser with the NUBM44, NUBM07E, and/or NDG7475 and I'm probably going to end up paying an experienced professional to build one for me. Before I go ahead and pay someone to build me one though, I wanted to do research into how to fix that horrible divergence and it SEEMED that corrective optics did an amazing job at fixing that issue, but I guess they are super hard to align and easily get moved in portable lasers. Depending on how much extra $$ its going to be, I may or may not still go down that route. Some day I think I might build my own lasers, but for now I'd much rather have an experienced hobbyist do a build for me.
Okay, I need some of you guys to help me explain all of this, but HighPower is obsessed with this divergence number I suppose :na:

Divergence is something we all enjoy being low, but it's not the only factor in a build especially portable. I would suggest going for a low divergence lab build if you want something practical, or even a projector. If you want to get regular use out of a handheld for burning and such then use a beam expander on the build, the higher the expansion the better divergence you will get..

You can use corrective optics on a handheld as well, sure... but if you bump those glued optics then it will be jacked up.


Also, the issue with the line as a dot; You will never even really tell a difference at close up burning.
Where will you be aiming your 2w+ multimode diode that you are so worried about it being a bar? I honestly can't think of anywhere I could point to unless I was out in the country and having fun... then I still would be just fine with a beam expander. In example 10x BE from JetLasers
 
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ElectricPlasma

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You can use corrective optics on a handheld as well, sure... but if you bump those glued optics then it will be jacked up.
Not sure why people are saying this. I think it's because it varies from what adhesive you use? For lenses, e-poxy comes to mind, and that will usually break before it will flex. I'm actually not sure of many glues that flex other than maybe hot glue.
 




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