Broken 532nm DPSS Laser Pointer

[fedcas]

Hi,
some time ago I bought a cheap 5mw laser pointer on ebay. I used it for a while, then I modded it to increase the current and after a short time it stopped working. Ok, everything seems normal, I knew that this way the diode life will be dramatically shorten...

but it is not the diode who has died! it still works perfectly... it's the optics. Nothing exits from the optical group, no green light but no ir light as well.
The optical group should be composed only of 2 crystals and the collimating lens afaik... so i really can't understand, how can a piece of crystal be "burnt out"???


And also another question related to dpss: are crystals all the same or are they proportionate to the power of the diode? In other words, put the case that a 5mw green laser has a 25mw ir diode: if I take the crystals and use them with a 250mw ir diode would I have an output power near to 50mw or this is not the way it works?

Thanks

 

[fedcas]

with stopped working I mean nothing exits from the optical group, no green light and no ir light (watching with a camera that is sensible to ir light)

I'm new to the forum, so you mean this is not the right place for this kind of questions? I mean, I've seen that you talk mainly about commercial lasers in this forum, but maybe a few of you are experienced also in diy...

 

[randomlugia]

Then how do you know if the diode is dead? And yes, too much light will burn out the crystals, which are only meant to handle a certain amount of IR. If anything optical is misaligned or broken and the diode works, you would see IR.

 

[fedcas]

I've disassembled the laser pointer and tested the diode alone, it works properly: it emits IR light and if I collimate it with a lens I'm able to project the laser spot (checked with a ir-sensible camera).

So I guess the diode is ok.



By the way, I've found an interesting link that answers my question about changing the diode with a more powerful one: http://www.casix.com/product/prod_opt_laser_dpm.html

I've also opened the optic group and what I've found is a cystal similar to those in the above link, ie nd:yvo4 and ktp coupled together:

at a visual analysis the crystal is ok: no burns or other strange things and it appears clear looking trough it.
But i'm trying to pump it with its original diode and with another 808nm (more powerful) diode that I have... and nothing seems to happen :s i really can't undersand...

 

[Kenom]

You've burnt out the crystals. The crystals are only capable of putting out so much energy before the coatings (which is what you burnt off) can't handle it. The pointer you had was only capable of handling a few mw of IR and you exceeded that. If you were to get a new set of crystals you would find that the laser you have would work again.

 

[bshanahan14rulz]

Kenom, I had a greenie a long time ago too, and the crystal was sooooo tiny! anyways, I took the whole thing back apart but could only get feint glimmers of green. From my observations, I noticed that normally I'd see no green, but if the crystal were aligned just right, I could coax out a little bit of green.

My question is this: was my crystal burnt out, or is there more to alignment than simply making sure the laser light hits the face of the crystal at 90 degrees? Like, when aligning a crystal, does its rotational position also matter?