New Gadget - 355/532/1064 Q-Switched YAG

[diachi]

Sorry for the double post, figure I waited long enough though!

Managed to get a couple beam shots last night. Not the best unfortunately, really needed more smoke in the air.

The divergence is still quite high, can't do much about that until I have better optics. Hopefully I'll be able to get a tighter beam and some more power then. Going to take me a while to get all of the necessary parts.

 

[paul1598419]

Oooo! I like it. I am envious, diachi. Why didn't you get some of the 532nm running? I'd love to see that as well.

 

[diachi]

Oooo! I like it. I am envious, diachi. Why didn't you get some of the 532nm running? I'd love to see that as well.

All of the 532nm lasers I have are much more powerful than the dye laser, so they'd have washed out the image. The 532nm pump was of course pumping the dye, so there's really not much coming out the other end. :beer:

Once I get the power up and divergence down it should be doable!

 

[paul1598419]

I didn't mean for you to do beam shots of the dye at the same time as the Nd:YAG 532nm laser. Just would like to see some beam shots of it. You got so very, very lucky with this laser.

 

[diachi]

I didn't mean for you to do beam shots of the dye at the same time as the Nd:YAG 532nm laser. Just would like to see some beam shots of it. You got so very, very lucky with this laser.

Ahh right! Fair point, I posted some beam shots but they weren't great. I'll need to get some better ones and post them! That beam is tight!

 

[Alaskan]

Luck of the Scottish.

 

[paul1598419]

Thank you. I will look forward to those. I know it will be something to behold.

 

[Laserbuilder]

Managed to get a couple beam shots last night. Not the best unfortunately, really needed more smoke in the air.

Very cool!

 

[LSRFAQ]

Do me a fave, seal her back up and get a dust free desiccant canister near the THG... Trust me on this, cleaning those big crystals is a witch and the solvent used is very very hard to get for amateurs. You need an air puffer with brush (NOT CANNED AIR) to gently blow off any dust that is already there.

Aligning for 355 is painful as the crystal has a very long thermal time constant. It will act aligned for a few seconds with a very high peak power out , then heat up, the power falls, and you'll need to trim it again. Can be on the order of a half hour job or more. There will be two or three false peaks and ONE real one. You have a couple of crystals there in the 1500-2500$ minimum replacement class.

Damn, gotta get me one of those.. Forget the dye, you may have just enough UV energy to power a small four mirror OPO.

Steve

 

[paul1598419]

Good to know, Steve. I normally don't open my SHG or THG lasers unless it is necessary as I am always concerned about contaminants. Even though the temptation to look is overwhelming, I do try to resist as I don't want to go through any of what you are warning about.

 

[tripmitz]

Hey diachi - nice work. Your posts here on the smartbeam are what bought me to LPF. I happen to have two of these units, one in working condition. The older one has seen a LOT of pulse shots and is pretty done in now after >4 billion pulses.

Just as a piece of info these smartbeam lasers were originally modified Azura MALDI 200 lasers lacking the rear digital control interface.

 

[luke-thomas]

Hi Diachi,

Firstly, I apologise if I was not meant to reply to this thread with it being an old one.

I am a 17 year-old student from the UK and am new to this forum. Long story short, I set up and run a laser cutting and engraving company in the later years of school. I came across a non-working Cerion 3D subsurface engraving machine. I purchased it hoping it would be something simple but as I slowly ticked off problems such as door interlocks it has got more and more complex.



I will attach some photos. I am responding to this post because this forum is literally the only post on the entire web I can actually find some direct crossovers of the equipment I have got. From the research I have done, my system should emit 532nm light to engrave glass crystals. As far as I know, this should be achieved by pumping a Nd:Yag crystal with the 808nm 50w pump diode, releasing 1064nm before SHM occurs in the non-polar crystal resulting in the 532nm light being produced inside the optics box. With me being fairly familiar with mirror alignment on the CO2 laser, I decided to take a look at the mirror alignment within the optics box. Well what a learning curve this has been. Just when I thought Physics couldn't get any more complicated. I am now thinking I should never have opened the optics box now I know more about it.



I have been speaking with Zenodilodon (I saw one of his videos on DPSS lasers and seeked help). We think we have now narrowed it down to a duff laser pump. We have really been struggling to find specific spec sheets for the diode (or any components really lol...). We started by measuring the voltage across the diode. This was STRANGE. I first achieved 1.6v when the laser is meant to be firing (1.36v between pulses). But the suddenly I received a reading of 2.7v when firing! This was extremely alarming. I then attempted to test the current sensing resistor by measuring the voltage across there. But with the 4 pin kelvin setup, I got weird results there to. The outside pins showed 0.024V whilst the inside pins showed 0.012V. From everything we know these should be the same shouldn't they?



I also have just built a very very rough spectrometer so that I could attempt to analyse the pump output somewhat. It showed a very broad peak but also, the output straight out of the pump (with no fiber connected) almost looks like a diffraction grating. This alarmed us too. I would be interested to know if this grating like pattern appeared on yours...



I am sorry to bombard with you with so much information and questions but I just felt I had to contact you because you are the only person on earth right now I have seen with a laser system just like mine. Now I know a little more about them, even not working I think we can both agree that are one hell of a kit.

I am so so determined to get this 532nm green light out of the other end of the optics box and firing through the galvo heads so I can start the just so lengthy process of getting it to engrave a crystal as it should. I have only ever seen a faint green light after aligning the mirrors using a laser pointer through the fiberoptic cables.


Kindest Regards,
Luke.

 

[hakzaw1]

great pics-- I see you having a bright future (no pun intended)--we want MORE!!

 

[luke-thomas]

great pics-- I see you having a bright future (no pun intended)--we want MORE!!

After many, many hours I still haven’t managed to get it working as it should. Excuse my forum uselessness but is there a way I can contact Diachi? It doesn’t allow me to message them privately...

 

[diachi]

Hi Diachi,

Firstly, I apologise if I was not meant to reply to this thread with it being an old one.

I am a 17 year-old student from the UK and am new to this forum. Long story short, I set up and run a laser cutting and engraving company in the later years of school. I came across a non-working Cerion 3D subsurface engraving machine. I purchased it hoping it would be something simple but as I slowly ticked off problems such as door interlocks it has got more and more complex.

View attachment 72350View attachment 72351

I will attach some photos. I am responding to this post because this forum is literally the only post on the entire web I can actually find some direct crossovers of the equipment I have got. From the research I have done, my system should emit 532nm light to engrave glass crystals. As far as I know, this should be achieved by pumping a Nd:Yag crystal with the 808nm 50w pump diode, releasing 1064nm before SHM occurs in the non-polar crystal resulting in the 532nm light being produced inside the optics box. With me being fairly familiar with mirror alignment on the CO2 laser, I decided to take a look at the mirror alignment within the optics box. Well what a learning curve this has been. Just when I thought Physics couldn't get any more complicated. I am now thinking I should never have opened the optics box now I know more about it.

View attachment 72352View attachment 72353View attachment 72358

I have been speaking with Zenodilodon (I saw one of his videos on DPSS lasers and seeked help). We think we have now narrowed it down to a duff laser pump. We have really been struggling to find specific spec sheets for the diode (or any components really lol...). We started by measuring the voltage across the diode. This was STRANGE. I first achieved 1.6v when the laser is meant to be firing (1.36v between pulses). But the suddenly I received a reading of 2.7v when firing! This was extremely alarming. I then attempted to test the current sensing resistor by measuring the voltage across there. But with the 4 pin kelvin setup, I got weird results there to. The outside pins showed 0.024V whilst the inside pins showed 0.012V. From everything we know these should be the same shouldn't they?

View attachment 72360

I also have just built a very very rough spectrometer so that I could attempt to analyse the pump output somewhat. It showed a very broad peak but also, the output straight out of the pump (with no fiber connected) almost looks like a diffraction grating. This alarmed us too. I would be interested to know if this grating like pattern appeared on yours...

View attachment 72361

I am sorry to bombard with you with so much information and questions but I just felt I had to contact you because you are the only person on earth right now I have seen with a laser system just like mine. Now I know a little more about them, even not working I think we can both agree that are one hell of a kit.

I am so so determined to get this 532nm green light out of the other end of the optics box and firing through the galvo heads so I can start the just so lengthy process of getting it to engrave a crystal as it should. I have only ever seen a faint green light after aligning the mirrors using a laser pointer through the fiberoptic cables.
View attachment 72354View attachment 72355

Kindest Regards,
Luke.

That pump diode looks fine, those stripes are normal. High power diodes like that are actually a stack of lower power diodes so you get an output that has a bunch of high intensity stripes. Mostly why they fiber couple it, you want a nice round even beam for pumping the crystal and fiber does a good job of homogenizing the beam. Can't speak to the power output, as that's practically impossible to judge based on a photo.

Without being able to verify the output power of the pump diode the things I'd check for first are damaged fiber (any sort of contaminant on the ends of the fiber will result in it getting burned), then I'd check for damaged crystals. Too much power density in the wrong place can crack them, and KTP (the frequency doubling crystal that converts 1064nm to 532nm) is known to degrade with use, especially in higher power applications. I've seen cracked crystals lase, but not well. Contaminants on the faces can also cause issues, either cracking or burnt/otherwise damaged crystal faces. After that alignment could be an issue, and getting it right without practice isn't all that easy. Though from what I recall it is a fairly simple linear resonator with frequency doubling done outside of the laser resonator, which makes things a little easier.

A lot of the components in that head are the same as mine, but the layout is different and there's a couple things in there that my head doesn't have. Could you post a top down picture? Would make it easier to understand the layout.

Sent you a DM, you should hopefully be able to message me now. I'm far from an expert on this sort of thing, but hopefully I can point you in the right direction.

 

[hakzaw1]

yeah I think there must be a sys 'glitch' as I have not been able to PM a few myself..