Yesterday I acted on the 2 lenses on the ir path to shift the beam vertically and superpose it to the red.

I placed the pinhole on the translation stage and moved it back and forth along the optical axis to maximize the power on the power-meter.

Then I did a scan of the surface reference sample that showed little improvement (R~12.5).

Matteo noticed that the crossing of the 2 beams did not correspond to the ir waist position.

I wanted to move the lenses on the ir path lateraly to shift the beam.

However, I found out that the first lens was not fixed at all : the mount got easily out of the fork and I had to unscrew the fork to fix the lens...

I tried my luck to recover a good position of this lens by hand but it is too sensitive (even though for a brief instant I could see R~18 which is the expected value, it was not possible to fix it at this position alone) so I'll have to restart the ir alignment...