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can i replace a burned ir dl on a dpss laser?

Xenom

Xenom

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hi, i have one of the famous chinese green laser pointers. After i played with the pot (lol) i burned the ir pumping diode.
So, can it easily replaced, maybe with another one a little more powerful (not too much, i know the dpss crystals cannot withstand big optical stress) ?
There are alignement problems? The crystal Island glued on a brass ring which is also glued on the brass case of the DL.
 





You are going to need to post photographs of the laser, or at least let us know what it is, if you can link to a URL showing it?
 
gozert said:
The laser, not the diode. It's probably not worth replacing the IR diode on such a cheap chinese laser. Just get a new one.
Click to expand...

i disassembled it. Anyway, i can get a replacement diode (200 mW) on ebay at about 4$, it's a lot more affordable that a decent green laser pointer... If there isn't too many alignment problems, i can try to reassemble the laser.

As we can see on the picture, the crystal is held by a brass cylinder, which can easily removed from the DL case (remove the crystal support i think is the only way to remove the DL from it's case).

But i don't know nothing about polarization, alignement and optics on the DPSS stystem
 
You have yourself a new laser from Gearbest for $7.22 and free shipping. Why try aligning an IR diode when you have no experience with it at all for 3$ less?
 
OK first off that diode is pressed in so in order to remove it you will need to remove the crystal mount.

then press out the diode after that you need to find an open can laser diode and using a press tool you will need to press the new diode into place. then wile wearing IR goggles and ones for the green light as well.

When I do it I use These goggles on top of a pair for green light.

after that you would need re glue the crystal with Optical adhesive (not epoxy since it walks as it dries) to the laser wile still holding it in alignment.

Bottom line is like stated before you are better off just buying a new one.
The Optical adhesive that is used to attach those crystals is a UV adhesive and runs about $20-30 a bottle and a true Uv led that would you would need to cure it would run you another $30.


and this time don't pot mod it :beer:
 
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gozert said:
You have yourself a new laser from Gearbest for $7.22 and free shipping. Why try aligning an IR diode when you have no experience with it at all for 3$ less?
Click to expand...

WTf, 7$? it cannot be better than this which i burned lol... Good price, maybe i'll buy it.

lazerman121 said:
OK first off that diode is pressed in so in order to remove it you will need to remove the crystal mount.

then press out the diode after that you need to find an open can laser diode and using a press tool you will need to press the new diode into place. then wile wearing IR goggles and ones for the green light as well.

When I do it I use These goggles on top of a pair for green light.

after that you would need re glue the crystal with Optical adhesive (not epoxy since it walks as it dries) to the laser wile still holding it in alignment.

Bottom line is like stated before you are better off just buying a new one.
The Optical adhesive that is used to attach those crystals is a UV adhesive and runs about $20-30 a bottle and a true Uv led that would you would need to cure it would run you another $30.


and this time don't pot mod it :beer:
Click to expand...

why use optical adhesive? cannot i use normal epoxy, or silicon?

Anyway, i get the idea of replace DL because it can be interesting if i get a little more power using a stronger DL. Because i have already the crystal and optics... So it can be a cool experiment
 
Xenom said:
WTf, 7$? it cannot be better than this which i burned lol... Good price, maybe i'll buy it.



why use optical adhesive? cannot i use normal epoxy, or silicon?

Anyway, i get the idea of replace DL because it can be interesting if i get a little more power using a stronger DL. Because i have already the crystal and optics... So it can be a cool experiment
Click to expand...


Optical adhesive because other adhesives can fog up your optics.

You may not get more power using those crystals, there's only so much they can manage before they become saturated and won't produce any more light. Up the power too much and you'll either crack the crystals or burn the coatings off of them.


Not to put you off, you should certainly experiment! Just don't get your hopes up too high! Also, make sure you have safety glasses for 808/1064nm, and 532nm ideally.
 
Xenom said:
WTf, 7$?



why use optical adhesive? cannot i use normal epoxy, or silicon?
Click to expand...

you don't want to use anything soft because it will shift positions with temperature.

wile epoxy would work you would have to hold the crystal in alignment as it dries so unless you feel like holding it for hours or making a jig to hold it your better off using UV adhesive that's instant (assuming you have a good UV light source)

One final thing what was the rated output for that laser? you may need more than 200mW of 808nm.
:beer:
 
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those crystals don't handle much, and replacing the diode not only messes up your alignment and focus, but your phase-matching and polarization as well, and alignment is hard if you don't know how to do it. its not just so simple as lining up all the parts, and fractions of a mm count, plus rotation, plus pan and tilt of all the parts, their spacing and focal points, keeping the temperature low enough to lase while lining it up....its honestly not worth the trouble. buying a new pointer really is your best option. It'd be fun to keep as a plaything if you're interested in learning laser physics, but realistically your chances of making a good laser out if it with no experience or the proper tools are very slim. they're not made to be disassembled. Real/good lab quality laser diode modules for greens that are still >$50 for a few mW when new unless they come from surplus, and even then, they still can be quite pricy.
 
Have fixed a similar module years back. It wasn't a big issue at all. The alignment isn't so difficult because the whole laser cavity just consists of the small crystal set (YVO4 & KTP with proper coatings) you see on your pictures. Often there's a small beam expander (two additional lenses) which might be more critical when it comes to alignment :-).

To glue the optics back in place you can use any solvent free adhesive.

But please keep in mind - in general it's not worth to repair such cheap laser modules - but it might give you some good feeling :beer:
 
mojo_1234 said:
Have fixed a similar module years back. It wasn't a big issue at all. The alignment isn't so difficult because the whole laser cavity just consists of the small crystal set (YVO4 & KTP with proper coatings) you see on your pictures. Often there's a small beam expander (two additional lenses) which might be more critical when it comes to alignment :-).

To glue the optics back in place you can use any solvent free adhesive.

But please keep in mind - in general it's not worth to repair such cheap laser modules - but it might give you some good feeling :beer:
Click to expand...

To add to that - If you are gluing the crystals back in place you should wear some latex gloves while handling the crystals in order to avoid getting grease/dirt on the crystal faces. That'll really mess things up.

Seeing as they are so small you're probably better just to use tweezers and avoid skin contact completely.
 
true, but we're getting off track. he'd still need to replace it with a similar open can LD and some patience, some quick dry epoxy or low stress adhesive, and clean gloves at a minimum. and assuming the new diode has the same output characteristics, what he'll get may be anywhere from nothing to perhaps 50mW at best with poor cooling, assuming he doesn't need presses to remove the diode. I know some of those modules are press-fit, and some are retained by rings.
 
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