I realigned the beam at normal incidence using the razor blades using input power of 1.59mW.

After realignment, I got angle of incidences of 0.009 deg and 0.0059 deg for vertical and horizontal direction respectively.

I tuned the input HWP and QWP to have input s polarized light by minimizing the p polarization component.

With current configuration, 'DC' corresponds to S pol and 'AC' to P pol.

I took 10mn of data with each polarization to finalized the setup calibration.

I was planning to measure the ILM sample birefringence but could not find suitable holder (30mm diameter ; 15 mm thickness).

We plan to start instead with spare ETMY measurement.