Lasever

[dave]

Aaron;

Once again you have proved that you are the king of the smileys! And actually I don't mind getting the MR head vs the larger U series head. So long as the laser works I'm happy.

SBK:

My old MR head (the one that failed) never even got warm to the touch, much less hot. It was mounted on an aluminum base plate the entire time.

The idea of using just one TEC for the entire head (rather than having two separate TEC's, one for the diode and one for the crystal) may be part of the problem, but I haven't been able to prove that they are ini fact only using a single TEC. (Looking at the driver board seems to suggest that they are, but I'm not certain.) Either way though, it's good to know that folks on the laserfreak forum are also aware of the issues and are working to help solve them.

Adam

It is a single tec design - David has even admitted to that in a post a while ago.

[buffo]

It is a single tec design - David has even admitted to that in a post a while ago.

Really? I must have missed that post. Ok then, that puts it in a different light.

Interestingly enough, Astroguy received an e-mail from David Wu recently, and in that message David seemed to suggest that the problem with the lasers were caused by failure of the optical coatings inside the cavity and not from any heating or cooling issues with the TEC.

I guess we'll have to wait to hear more from David to be certain though.

Adam

[dave]

Really? I must have missed that post. Ok then, that puts it in a different light.

Interestingly enough, Astroguy received an e-mail from David Wu recently, and in that message David seemed to suggest that the problem with the lasers were caused by failure of the optical coatings inside the cavity and not from any heating or cooling issues with the TEC.

I guess we'll have to wait to hear more from David to be certain though.

Adam

That actually would not surprise me, as we have never had any issues with the red diodes.

[sbk]

Failure of optical coatings? So they go over the damage threshold of the crystals with the pump diode power??

[buffo]

Not so much a failure of the crystal itself... It's more likely that the specific wavelength reflective coatings on the intra-cavity component faces break down after a few months use. Then you start leaking IR (either 808 nm or 946 nm) out of the cavity and your efficiency goes to hell. (Which explains why the power output drops way off, but not all the way to zero.)

Adam

[da2001]

2 Month later.

Still waiting.
He promise every day, that he will send the laser tomorrow back.

I have a few well-known in shanghai. So they will go directly to him, if they still didn`t send my laser.


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