I use the begining of the set-up of the LCD and after the QWP and the HWP I put a lens f=100mm, and I characterize the beam.
Before the lens, w0 = -47,1 mm ; z0 = 26 μm , after the lens : w0 = 88.8 mm ; z0 = 49.2 μm
I moved the lens f=100mm after the characterization at d = 0.2 m (d = 0 is the same has the previous characterization)
!!!! The zero of reference did not correspond to any optic know, but it's at 101,5cm on the ruler, or the third a hole after the HWP.