!!! strange FP cavity behavior => impossible to lock !!!, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
|
this morning, we tried:
- to move a bit the arm of the L-shape off the beam axis (in case of it could have touch something and induce vibrations) => no effect
- to change the CEP to get an equivalent lower Finesse => weak improvement |
|
!!! strange FP cavity behavior => impossible to lock !!!, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
|
it could be also an optical unstability, as when the intra-cavity power increases, the radius of curvatures of the mirrors increases too due to thermal
effect, and then one could go in the instability region.
but if it was the case, by reducing the power in the FP-cavity, we would also reduce the thermal effect and then, we would come back in the stability |
!!! strange FP cavity behavior => impossible to lock !!!, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics 
|
This morning,
- I installed the fast feedback loop.
now, the error signal goes to the Laselock AND |
|
!!! strange FP cavity behavior => impossible to lock !!!, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
|
this afternoon, in adjusting the CEP and improving the parameters of the lock, I was able to get ~ 47kW stable inside the cavity, always for 30% of laser
amplification ratio.
it confirms that the Finesse, and then the gain of FP-cavity, has suddenly increased thanks to some "mirrors surface cleaning" |