Don,

Our Millenia isn't even 1 year old and had more or less the same problems.
The technician was called in: he slightly realigned it and redid the SGH
temperature settings.  Apparently, even with very small temperature
fluctuations in the room, the laser needs to get accustomed to the
environmental conditions and this can take a while.  So a small readjustment
after this 'incubation period' should do the trick.  Our system now is alive
and pumping !

Good luck,

Steve
___________________________________________________
ir. Steve Koll
PhD Student
Ghent University
Lab of Biochemistry and Molecular Cytology
Coupure Links 653
9000 Gent
Belgium
Tel:++32/9/264 59 70
Fax:++32/9/264 62 19
http://biochema.rug.ac.be/steve

>Dear List,
>
>I have a 1 year-old Spectra Physics Millenia Vs Diode-pumped laser on a
>two-photon setup. It has had about 220 hours of use. Initially when it is
>started, it will power up to over 5.5 W at 100% current. However, after
>about 30 minutes the power at 100% current starts to drop. By three hours
>it is down to about 4.5 W.  The temperature in the room is pretty well
>controlled- it varied by less than 2 deg C over the three hours. In
>addition, the bath temperature of the cooler stays very constant
>throughout. Does anyone have an idea what might be going on? A collegue of
>mine suggested that there may be a problem with the doubling crystal. The
>technician at Spectra-Physics wants to simply increase the amount of
>current going to the diodes to increase the power, but I am worried that
>this might shorten their lifetime, and not solve the underlying problem.
>Any suggestions?