You have to align the pump doubling crystal.  Thermal fluctuations can
cause drift.  I would push for a new head first (mechanical weakness
allowing drift) but otherwise you should get the service tech to show you
how to align the crystal mirrors which is not too difficult.  Increasing
current is more a bandaid than a solution.  At least the mirrors can be
adjusted - I believe the Verdi has fixed mirror mounts.

Ours (8W Millenia) did the same thing two months after installation and a
simple tweak did the trick for us but I have a promise for a new laser head
if it does it again.

At 02:32 PM 9/24/01 -0700, you wrote:
>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?

Derek Schulze
Flow Cytometry and Confocal Microscopy Facility Manager
Cancer Research Labs
Queen's University
Kingston, ON
Canada