Matteo, Simon

Since the DC value seems to be depending on the longitudinal position of the mirror-substrate (Z), we repeated taking a XY-map at Z=112 with re-calibrated DC-value. It turned out that also the absorption-values increased. We now think that we would have to readjust the DC value every time the Z-stage moves, which would make it basically impossible to receive any quantitative results on XZ and YZ maps (however, qualitative results are anyway achievable).

We run another map at the center position with adjusted DC value to have the three maps (Z=46, 79, 112) all adjusted.

At the same time we started to reconfigure the absorption bench for measuring polarization maps.
Therefore, we aquired some PBS and a 2" lens (f=100) which we could put in the outgoing beam path. In a first test, we already recognized that the main part of the pump beam is p-polarized with ~10% s-polarization, although we thought it were merely s-polarized!
So, we put another PBS in the incoming beam-path to make it almost completely p-polarized and checked the effect on the photometer. When moving the mirror into the beam-path, there seems to be some changes happening but without more precise analysis with photo-diodes, we cannot be sure.
Anyway, we let it like this and will continue tomorrow when the other absorption measurement is finished.

At last, we removed also the first-contact from the ETMY substrate which we put there to clean its surface after the laser-burning accident last week. It seemed to be successful and we could not see any dirt anymore. In this state, we put the container over the substrate to protect it.