Simon
(This is the report of the last two days activities)
I finished the recalibration of the PCI were I slightly adjusted the position of the pump-beam and used (now) the correct way of the surface calibration sample.
R_surf = AC_surfref/(DC_surfref*P_in*abs_surfref) = 17.2 [1/W]
where AC_surfref = 0.48V, DC_surfref = 4.07V, P_in = 0.031W and abs_surfref = 0.22
R_bulk = AC_bulkref/(DC_bulkref*sqrt(T_bulkref)*P_in*abs_bulkref) = 0.784 [cm/W]
where AC_bulkref = 0.09V, DC_bulkref = 4.8V, T_bulkref = 0.55, P_in = 0.031W and abs_bulkref = 1.04/cm
Both values indicate that the AC/DC ratio is higher than before and hence, the crossing-point is indeed more at the pump beam's waist.
After the calibration, I changed back to the spare ETMY and made a scan along Z (c-axis) where you can see some interesting structures both in AC and phase at around Z=55 and Z>90 (see attached screenshot).