DPSS 532 - has developed 2 spots

[norty303]

I have a CNI MGL-H head that I thought was out of alignment with the red/blue, until I tweaked it a bit and found that I got a line out the other side as I moved it right! It appears I have a beam with 2 spots!

I projected a spot on the wall at varying intensities, and it is visible throughout.

The attached pics were done one click above lasing threshold (to avoid as much blooming as possible), at about 2m range.

Is there anything I can do to correct it, I've never been inside a DPSS before.

Am I right in thinking I'll probably need some IR safety glasses to do proper adjustments, or are there methods you can use to avoid getting a 'dose'?

It's only rated at 500mW, but doing about 800mW still.

[steve-o]

It appears that your DPSS might have gone TEM01:


Realigning the xtal may cure it .. not sure .. Maybe some DPSS experts will chime in ..

-edit- YES YOU WILL need 808nm safety goggles OD5+ to work on this .
The other option is using a ccd camera to perform the adjustments.

[Kingsoflight]

If it wasn't like that before then the crystal has moved ever so slightly remember the IR needs to pass straight through looks like your getting side bounce in the crystal when I converted my blues to green I'd get the same effect till you get it just right I did it without glasses all of the opening was covered by my hands and I only looked at the spot on my target till aligned then held it, shut it down, then CA glued it to the TEC.

[Steve Milani]

Hi Norty

Sorry to hear this mate...
Me too have (still have) the same problem with my CNI 500mw MGL-H green... It's seem to be gone to TEM 01...
Take a look of first picture: it show a "double" line at about 8 meters far from module. Power is ok: 630mw (labeled 500mw).

I asked infos and solutions to Steve *mixedgas* and this has been his valuations: sure at 99% it lost its crystal alignment.
Unfortunately my hands are not so good anymore.... my eyes too...
Too risk to me trying a "surgeon-operation-at-opened-heart" inside the module...

What about to send the module to Rob *stanwax*?. I think he could fix it (crossing fingers...)

[polishedball]

Can't a blown TEC cause it to go into this mode?

[norty303]

Ok thanks folks. Is the crystal the part in the middle just after the diode in Steve's picture?
I'm assuming the large part covered by the plastic cover is the SHG right?

[TechJunkie]

Can't a blown TEC cause it to go into this mode?

I think if it was a blown TEC it would be mode hopping from the heat. Its common in high power 532 handhelds. Because its staying in tem01 its more than likely alignment.

[Kingsoflight]

The part in the middle should be a focusing lens what has move is under the plastic cover there should be a aluminum sled with all the goodies on it more than likely it came unglued from the top of the TEC which I've had happen on some of my blues and the plastic cover was the only thing holding it down on the TEC so it moves you have to take the cover off and touch I to see if the sled is still glued to the TEC.

[jeejeedr]

I just worked on one yesterday. I think from the second photo that the optics (middle component) is out of alignment.
The part where the bottom scre is in the photo should be more to the right. (unless the optics are glued in a wrong angle)

Before loosening that screw I would mark the position of the mount so you can return it to the same position if needed.
Also, to rotate just a bit, dont loosen the top screw in the picture completely.

Hi Norty

Sorry to hear this mate...
Me too have (still have) the same problem with my CNI 500mw MGL-H green... It's seem to be gone to TEM 01...
Take a look of first picture: it show a "double" line at about 8 meters far from module. Power is ok: 630mw (labeled 500mw).

I asked infos and solutions to Steve *mixedgas* and this has been his valuations: sure at 99% it lost its crystal alignment.
Unfortunately my hands are not so good anymore.... my eyes too...
Too risk to me trying a "surgeon-operation-at-opened-heart" inside the module...

What about to send the module to Rob *stanwax*?. I think he could fix it (crossing fingers...)

[ionlaser555]

Ok thanks folks. Is the crystal the part in the middle just after the diode in Steve's picture?
I'm assuming the large part covered by the plastic cover is the SHG right?

The part with the plastic cover will be both the KTP and YVO4 or YAG crystal , the YVO4 sits at the 808nm side glued on the inside with the lens focusing the 808nm light into the YVO4 after that is the KTP that sits in a small copper block , then at the other end is the OC mirror , So the whole 808nm to 1064 to 532 happens under that plastic cover . The 473nm CNI blues do the same to keep the crystals in a sealed environment .