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Does anybody know why my laser suddenly started changing shapes??? And how to fix it??? EDIT: I pulled off cap today and I don't know what to do next.

Fundles

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Are you trying to say that the temperature makes the crystals alignment change?
 

kecked

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That can happen or the crystals thermal lens or or or ton of reasons none easy to fix. If it’s a pointer toss it.
 

Fundles

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:/ well thanks. Not gonna toss it, gonna use it as a guinea pig I guess.
 

paul1598419

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You can buy these on eBay for $6.00 each with free shipping. None of the sites that sell them actually make them. Regardless of where you buy one they are basically the same laser. Just buy 2 or 3 of them from different sellers. You will get some good ones.
 

Fundles

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Yep thanks. Honestly half the fun is cracking them open and see what makes them tick tho.
In fact with this mode shifter I just now tried prying the module out, slipped and the expansion lens or whatever it is separated from the crystal set and went flying! Maybe one day I'll find it LOL. Anyway, the green beam is clearly BARELY coming out of the corner of the little shiny square which I assume is the KTP crystal. I'd like to try and realign the crystal set because it looks wrong. Just for the hell of it. Also, now with that lens "removed" I can clearly see a red beam leading up to the crystal (!!!) I feel like superman or something I can see invisible light! So now onto a couple more questions. And thanks a lot you guys for helping me learn.

1. What optics would I need to turn this into an 808nm laser? I still have the focusing lens, would I need a second lens?
2. What chemical is good for dissolving the black glue holding the crystal set to the module? Acetone? Would automotive brake cleaner work? I saw a video about it a few weeks ago but I can't find it again.

Thanks a lot, I've learned a lot so far since finding this forum.
 

absolute

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You might feel like superman now but if you keep looking at that "red" beam you'll actually end up being able to see a lot less than a normal man.

I've learned a lot so far
Please, for the sake of your eyesight, learn more about safety before proceeding.

To give you hint: if you can see a faint red glow that means the output of that near-infrared laser is so high your eyes can detect it even though they are almost completely insensitive to that wavelength. Which means more light is entering your eyes than you can see. This will cause damage the same way visible light does, and can blind you permanently.

If you plan to experiment like you are, at least invest in some quality safety goggles.
 

paul1598419

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If you want to turn this into an 808nm pointer you will need to remove the crystal set and add a collimating lens. Should be a glass lens too. But, even if you can see it, the beam is more powerful than it appears.
 

kecked

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The better bet is to keep the 1064. 808 is just a diode.
 

paul1598419

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The better bet is to keep the 1064. 808 is just a diode.
The problem with that is removing the KTP crystal from the YVO4 which are adhered together on the small crystal heat sink. It is theoretically possible, but not likely. You could try, but don't be disappointed if it fails.
 

Fundles

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I have 2 sets of safety goggles that block 808nm. Are you telling me viewing the beam (not the dot) without goggles is going to damage my eyes? Because I kind of doubt that.
I don't see a faint red glow I see a vibrant yet deep red line, the beam itself.

So anyway what's a good solvent for that black glue?

Edit: I was dead wrong the red line I saw was a reflection not the beam itself. My eyes are ok though. Also brake clean makes short work of the black glue.
Edit again: was definitely mode hopping from improperly aligned Crystal's. Now I just need to find that lens that went flying 🤔
 
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paul1598419

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I have 2 sets of safety goggles that block 808nm. Are you telling me viewing the beam (not the dot) without goggles is going to damage my eyes? Because I kind of doubt that.
I don't see a faint red glow I see a vibrant yet deep red line, the beam itself.

So anyway what's a good solvent for that black glue?

Edit: I was dead wrong the red line I saw was a reflection not the beam itself. My eyes are ok though. Also brake clean makes short work of the black glue.
Edit again: was definitely mode hopping from improperly aligned Crystal's. Now I just need to find that lens that went flying 🤔
Where did you get that from? I have never said the viewing either the beam or the dot on a diffuse surface without goggles would harm you. I only said the the light that you can see is far less powerful than the laser actually is. To me the dot is a faint dark red and the beam is not visible at all. Hence the IR camera. But, absent an IR camera you can see the dot enough to collimate the beam.
 




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