What happens when.....

[Things]

When a green laser stops working, usually you can still see a dim red IR light inside it. But what i am wondering is if the IR diode still works, how come it doesn't lase green anymore? I know the crystals can come unaligned, but thats not the case here. Is it possible to "burn out" the crystals??

 

[wooooooolazer]

I think what happens is when it dies it emits light like a regular dead dvd burner diode but when it dies it changes nm slightly causing the crystals to not change it into green so it lets thru all the ir without chaning it. But i think the diode is also dead, it will more than likley emit the same amount of light as a dead dvd burner diode, an expensive led.

Or i may be completely wrong here :-/

...lazer.... ;D ;D ;D

 

[pseudonomen137]

Many ways to kill a greenie unfortunately. Yeah, you can end up either knocking the crystals out of alignment, and sometimes there can be poorly made crystals which just crap out on you. If that's the case, the diode should be fine. You can also end up killing the diode too though! It would still emit some light like and LED, and on a poorly filtered laser you may see that through the aperture, so its a bit hard to say without knowing what part failed.

 

[Hemlock_Mike]

Interesting question -- I think wlaser is right but here's cause for experiment....

Measure your greenies for IR leakage and record it somewhere. When it dies, no green but a red dot, measure the IR again. If its = or > the original reading, its the crystals. If less, you have an IR LED.

Mike

 

[Things]

well the IR diode still burns, so thats Ok i guess. So the crystals can just "die"?? How so, you ruin their properties? or does it screw with the coatings or something?

 

[flogged]

well the IR diode still burns, so thats Ok i guess. So the crystals can just "die"?? How so, you ruin their properties? or does it screw with the coatings or something?

Crystals sure can just die. Do a search on 'KTP grey tracking' (photochromic damage). Poor quality xtals, or xtals that are overpowered undergo semi-permanent changes/damage (after use), and can take up to 24 hours to recover. It's a poorly understood process. There are many different grades of xtals available, depending on how they're grown, cut, etc. You'd better believe most pointer manufacturers are going to be using the cheapest crystals they can get away with.

The crystal set is what determines that overall efficiency of a green DPSS laser.. it determines what fraction of the pump diodes radiation gets converted to green light. Consider, for example, that all the NOVA lasers up to ~100 mW use the same power pump diode (500 mW) ... it's the xtal set that determines whether it's a 35mW or a 100mW pointer. The price spread between a 25mW and 100mW greenie should give you some idea how hard it is to reliably produce the more efficient xtal sets.


Of course it's also possible they can get knocked out of alignment.

 

[likewhat]

I somehow doubt that the crystal could be destroyed with the ultraweak intensities in these things, I have heard of that before but it was regarding the crystals used for doubling pulsed lasers, an alignment issue seems like a more reasonable reason for it to stop working.

 

[pseudonomen137]

I somehow doubt that the crystal could be destroyed with the ultraweak intensities in these things, I have heard of that before but it was regarding the crystals used for doubling pulsed lasers.

In a quality laser with good QC/manufacturing on their crystals that's entirely true. A 30mW green from China for $20 though? A little different, hehe

 

[Things]

Crystals sure can just die. Do a search on 'KTP grey tracking' (photochromic damage). Poor quality xtals, or xtals that are overpowered undergo semi-permanent changes/damage (after use), and can take up to 24 hours to recover.

They heal? So after 24 hours or so, they could work again??

 

[philguy]

well, recently my DX30 dropped to the ground and refused working, but not even IR is emitted (no matter how hard I stare into...haha, never mind!).

Could it be that it's just the driver, and my KTP setum might still work? Or is 1064 too deep for cameras?

 

[Things]

usually pump diodes are 808nm, and both of em should be visible to camera's.

 

[philguy]

Okay, I thought that maybe the 1064-conversion still works and thus it is not visible, but if it would anyways show up...



guess I'll have to dissect it

 

[Things]

oh after the conversion its 1064nm, but i think the camra could still pick it up. I think it depends on the camera. Most, almost all cameras can see 808nm, and a few can see 1064 too.