V****o DPSS Green has died, need help...

[Bbe]

Hello guys,

Came the end of the world, In my lovely 4W green laser power suddenly dropped to 0.3 watts. I disassembled the unit and after some research, i found that inside vanadate crystal has a small crack (had to look through a microscope) and on the surface of the LBO crystal has several dark spots. Diode, TEC, is functioning normally. I don't understand why this happened. The second 4W green, which works in tandem with it - works well, no hint of power reduction...
I have a few questions about the crystals that are used in this module. Probably the characteristics typical of all modules built in China.

-what's the Nd concentration in Nd:YVO4?
-what's the coating on surfaces Nd:YVO4?
-should i be concerned about a few dots on LBO surface?
-what is the possibility of damage to the front and rear mirror/lens?

And the most important question - where to buy good crystals for replacement?
PS: vanadate size - 3x3x5mm LBO size - 2x2x10mm

This is my first experience with a powerful DPSS, so I will be glad to hear any useful information.

Thanks!

[sbk]

Hi,

How old is the laser? (Years/hours)

Have you tried to contact Frank at Viasho? He's responding fast and he will quickly sort this out for you...

[Bbe]

Hi,
laser about two years old, but the mileage of about 100-150 hours. Second laser with the same mileage working like new.
I contacted with Frank, he offered me the crystals, but I want to "find out the reasons" before spend a heap of bucks to repair...

[sbk]

Ok strange, but I think the reason is simply "chinese cheaper laser", so defects happens, with every manufacturer.

But my guess about the best thing to do is you should happilily send it back to the factory so they can properly repair it, as you don't want to do it by yourself until you have a lot of experience in high power DPSS alignment, and patience...

[Meatball]

Those could be thermal stress induced damages. Might want to triple check your TEC operation and verify its working ok.

[planters]

I agree that you might just want to send it to Frank. I think if the TEC were working so poorly that you produced thermal fractures then you should have seen some degradation in alignment and output. I also have a Vashio (1.5W) that "died and then generated only 50mW after only the first 10 hours of use. Frank returned it to the factory for a new head and no problems for the last 16 mo.

[Bbe]

But my guess about the best thing to do is you should happilily send it back to the factory

Yes, of course. If it was under warranty, I would have done so. Otherwise, I need to pay for shipping, parts and work, I think that it will harm my budget around 1k$

Those could be thermal stress induced damages. Might want to triple check your TEC operation and verify its working ok.

I checked four times - temperature stable about 22C

This forced me to drink coffee and think ...
Of course, I was wrong about the LBO crystal. It's a KTP crystal, they used by many manufacturers at a pump power up to 15W. I has bungled a simple drawing of my laser:

Attachment 35210

Trying to shot the crystals. This KTP, clearly visible dot on the surface, which worries me:



And this is the main culprit - Nd:YVO4 crystal. Can see crack? Formed from overheating?



Preliminary verdict - replacing Nd:YVO4 crystal - 100%, KTP - 50/50
Oh, I almost forgot - I have tried to re-collimated and I managed to find the location of optics in which laser gave 2 watts.

[Picasso]

Great pics thanks for the posts Bde.

[laserdj]

I´m having the same problem here two units, (2w) from Viasho are now very low power... do you think I can try and fix them? Replace the crystal (what source)?
I live in Brazil and it is almost impossible to send it back, would end up costing a new head´s price =/

[steve-o]

I think I read somewhere (probably a Steve R post) that you can sometimes find / realign to a different (undamaged) area on the damaged xtal and get it back to good working condition . I don't know if your laser has that flexability/ capability tho ..