You have the beamlok box running correct? You know that the beamlok pickoff sensor sensor, in front of the OC, must be aligned as well as the cavity, correct? You know that the beamlok rear mirror is part of a deliberately unstable cavity and you probably do NOT have to move the front mirror, which does have both vertical and horizontal controls when you remove the front panel which is held in by magnets.
I highly suggest you write down your head serial, psu serial, and beamlok driver serial and call SP-NEWPORT, speak to a service engineer, and get a manual in PDF or paper. Because of beamlok, this is a actively corrected cavity and is NOT anything like the coherent when you tune the cavity.
The rear mirror has a convex, NOT concave, NOT flat, curve, and this means beamlok must be on if you want to see any stability. It has just enough designed in optical stability to stay lasing at 30-50% of rated power with beamlok off. Which is probably exactly what you are seeing. Beamlok moves the rear mirrors on piezo actuators in response to position changes on the quadrant position sensor mounted in front of the OC, there is a optical pickoff up there, and its position is adjusted by the three brass screws sticking out of the teflon block at the OC end. Removing the etalon knocked the optical path off enough that the feedback loop is not closing. The three brass screws are extremely touchy, and thus there is a pickoff alignment device included in the parts kit with the laser.
It would take me 2-4 hours to tweek beamlok with a etalon and UV optics. Doing it in the visible takes about 4 hours the first time and 1-2 hours thereafter. Beamlok is a real witch to learn at first and the pickoff adjustments interact as they are NOT kinematic, but are three screws with springs.
To remove beamlok you would still need to bias the piezos and change the rear mirror, if not the front mirror, too.
You do have the remote with the XY display, right?, and are NOT using the serial port?
And I'm curious, this laser is perhaps in Akron, Ohio??
Steve
Last edited by mixedgas; 06-22-2010 at 09:19.
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...