Marc, Yuhang

We went to check to End mirror OpLev : All optics seemed well fixed.

We tuned the beam height to be identical on the injection and detection windows.

We moved vertically the lens on the detection window to have the beam centered.

Unfortunately it didn't change the coupling of pitch to yaw visible in the figure 1 of the parent entry.

We can see that pitch couples to yaw but not yaw to pitch.

This seems to indicate that the sensing matrix of OpLev is not the culprit.

Furthermore, when we inject a line on the End mirror pitch, we can indeed see the beam on the FC transmission camera moving in pitch but not in yaw. Even if the OpLev yaw senses this line...

On input mirror we can see both pitch and yaw lines on pitch and yaw signals from the oplev so it could be solved by finer tuning of the oplev rotation matrix.