Rofin DPSS YAG metal cutting laser teardown

[celas]

I bought an unknown (used) laser head from local site. No info no datasheet, it turned out to be a high power diode pumped YAG laser. Look what I've found inside:

Large YAG rod in flowtube, appears to be in perfect shape

Diode compartments

Opened one

I'll have problems with testing these diodes because my power supply only supplies 3,5A - they just glow at this current, nothing more. Facets look fine tho, much better than ones on ebay listed as "Tested to be withing blablabla W". Maybe I'll finally have some decent pumps for dpss lasers. Nice

Btw, since I am quite a hypochondriac I need a little advice - when I opened this laser there was some coolant left inside, it wasn't water because it had quite strong off-sweet smell - any chance it could be something toxic/nasty or I shouldnt worry? Ofc I wasn't drinking it but I'm still concerned

 

[RedCowboy]

Did it look like this : https://www.ebay.com/itm/ROFIN-SINA...m=401520715866&_trksid=p2045573.c100033.m2042


Says 42 volts at 50 amps, I wonder what the output is ? It appears to be CW

Also I see it needs liquid cooling.

 

[celas]

Did it look like this : https://www.ebay.com/itm/ROFIN-SINA...m=401520715866&_trksid=p2045573.c100033.m2042


Says 42 volts at 50 amps, I wonder what the output is ? It appears to be CW

Also I see it needs liquid cooling.

Yes, it looked almost exactly like this. You can bid with confidence. I paid 100$ for it tho

Anyway, probably gonna dismantle this one for diode bars, buy next one and try to power it up as a whole. Would probably need Q-switch for it tho, no internal mirrors

Also there are 4 42v 50A modules stacked together, each contains 24 diode bars.

 

[RedCowboy]

I'm sure you lose a lot of power in waste heat pumping the YAG rod, but the beam quality should be much better, what comes out of those pump diodes will likely diverge something awful as well as being a diode stack in each diode block.

Maybe you could run it as built in short bursts without the liquid cooling or water jacket, maybe a single 1/4 second bursts every minute or so ?

Oh, no mirrors huh...... don't suppose the rod ends are mirrored ??


I have this little CCD camera, it sees IR very well, ( NO FILTER ) it has RCA AV jacks so you can connect to a TV monitor, runs on 9-12v or 3 li cells in series, made to work with 2-4 cells for quads FPV > https://www.ebay.com/itm/Night-Visi...710611&hash=item2aa38309cb:g:dacAAOSw7wxarOTh


Home security cams work well too.


p.s. You do know about eye protection...yes?

 

[Alaskan]

Nice find, could you post some more photo's of those diodes so I can get a better idea of how they are constructed?

 

[DashApple]

That's a Nice diode array .

The Liquid probably has some form of antifreeze in it giving the sweet smell .

 

[celas]

In order to test these diodes fully I need to supply at least 10A. Since I dont have regulated power supply strong enough for that, can I just use 3,3V line from ATX PC PSU? Or is it too 'dirty' (spikes, transients) and will kill the diode?

EDIT: Nope, doesnt work. When I try to power up with PSU it flashes for a split second and thats all. Can be repeated when i switch it off and on again but no continous outpus

 

[celas]

I'm sure you lose a lot of power in waste heat pumping the YAG rod, but the beam quality should be much better, what comes out of those pump diodes will likely diverge something awful as well as being a diode stack in each diode block.

Maybe you could run it as built in short bursts without the liquid cooling or water jacket, maybe a single 1/4 second bursts every minute or so ?

Oh, no mirrors huh...... don't suppose the rod ends are mirrored ??


I have this little CCD camera, it sees IR very well, ( NO FILTER ) it has RCA AV jacks so you can connect to a TV monitor, runs on 9-12v or 3 li cells in series, made to work with 2-4 cells for quads FPV > https://www.ebay.com/itm/Night-Visi...710611&hash=item2aa38309cb:g:dacAAOSw7wxarOTh


Home security cams work well too.


p.s. You do know about eye protection...yes?

Yea, I am only looking at it (and reflection, scattered or not) through my phone camera

 

[paul1598419]

Nice snag for only $100. I also have a CMOS camera meant for aligning IR too. It also has an RCA plug for video out, so I can connect to the TV as well. Bought it years ago specifically for this purpose. I would work towards building a driver for the diode arrays as my next step. I look forward to any results you might post. + Rep.

 

[celas]

Nice snag for only $100. I also have a CMOS camera meant for aligning IR too. It also has an RCA plug for video out, so I can connect to the TV as well. Bought it years ago specifically for this purpose. I would work towards building a driver for the diode arrays as my next step. I look forward to any results you might post. + Rep.

Since you are much more experienced, maybe you could answer my question (about this particular build) - with a YAG laser of this power Q-Switch is necessary or it would work properly if I attached right mirrors? And at this power mirrors should be water-cooled and thick, right? I could get unbelievable amounts of green if I doubled it, order of magnitude more than what is needed for dye pumping - making green laser out if it is my goal.

 

[diachi]

Since you are much more experienced, maybe you could answer my question (about this particular build) - with a YAG laser of this power Q-Switch is necessary or it would work properly if I attached right mirrors? And at this power mirrors should be water-cooled and thick, right? I could get unbelievable amounts of green if I doubled it, order of magnitude more than what is needed for dye pumping - making green laser out if it is my goal.

No reason you can't run it CW if you wanted, though the Q-switch is nice to have. You can still run CW if you have an AO Q-switch in place.

Shouldn't need water cooled mirrors... What sort of power is it rated for?

 

[paul1598419]

Diachi beat me to it, but since this is water cooled, it was meant to be run CW. You would only use a Q-Switch if it were optically pumped for one shot use. I would try to see what it needs to get it running CW. It is likely quite powerful, but need to know the specs on this unit to go further. You would also be in a better position to v double it to 532nm output. That would still be tricky as this was likely meant to just run 1064nm CW.

 

[diachi]

Diachi beat me to it, but since this is water cooled, it was meant to be run CW. You would only use a Q-Switch if it were optically pumped for one shot use. I would try to see what it needs to get it running CW. It is likely quite powerful, but need to know the specs on this unit to go further. You would also be in a better position to v double it to 532nm output. That would still be tricky as this was likely meant to just run 1064nm CW.

Water cooling doesn't indicate CW operation at all. CW pumped sure, but that doesn't mean the output has to be CW, the pump power would be the same either way. Plenty of water cooled Q-switched YAGs out there with a CW pump.

 

[paul1598419]

I should have been more specific. Yes there are Q-Switched water cooled lasers, but they have pulse rates in the kHz range as opposed to a one shot pulse. That was what I meant. And of course he can Q-Switch it if he wants to, but since it wasn't setup to run that way, I'd be trying to run it CW.

 

[Alaskan]

Wish we could see a better pic of the individual diode.

 

[paul1598419]

I would like to see photos of every aspect of this Nd:YAG. I'm not so sure it is without mirrors, but can't tell from the little bit I've seen so far. I still think it was a hell of a deal for the price.