Pengbo, Simon

Yesterday, we have finally set the FI in place and tried to get the laser beam through it.
We recognized that a proper adjustment stage would be desirable as it decreases the work. However, since we couldn't find a suitable one (or one which isn't used rigth now), we installed the FI-cage on top of two scalable posts and tried or luck with them. In the end, I think we could reach a good position and ca. half of the ligth passes toward the sample chamber (which is as expected since we still don't have the second HWP in front of the second PBS).
Also, in order to have a free space for the ejecting non-used beams, we removed one of the 4 bars of the cage-system for the FI. We think that this is not harming the overall stability of the system since it makes a very sophistictated impression anyway.

Judging from the laser card, the beam shape seems to be fine but we need to investigate it more deeper with the beam-profiler.

After setting the FI, we placed some beam-dumps in those positions were a non-used beam is ejected sideways from the FI. Unfortunately, these beams are under a non-rectangular angle and thus a damping is a bit tricky. We, however, used an elongated post to fix a holder where the angular position can be freely adjusted (see also attached pictures) for the beam that goes also upwards. For the other, we are utilizing a new beam-dump with a large opening so that also the transmitted light from the coated 45 deg mirror can be covered.