In order to further investigate the effects of the input beam incident angle we mesured the polarization angle as a function of the input beam polarization angle.

Data are attached to this entry.

Note that :

There are input polarization angle for which the s polarization power transmitted with sample is higher than transmitted s polarization power without sample..

The minimum s polarization seems to be reached for hwp  angle = 71 deg (ie 26 +45 deg) and using this polarization to normalize our signals means that the hwp angle = 341 deg that was assumed to be fully s polarization is in fact 10 deg polarization angle...