NAOJ GW Elog Logbook 3.2
Displaying report 1-1 of 1.
MarcEisenmann - 23:27, Thursday 13 February 2025 (3906)
restart of birefringence measurements
[Marc, Michael Miller]
Had to change COM of Zaber from 6 to 7.
We installed the 2 blades on translation stage.
Vertical cut at : 310 80 20
Horizontal al cut at : 380 140 20
last mirror is at 175 mm from blade when the blade is at 20mm.
MAX DC = 0.25V
After realignment, we reached about 0.07deg AOI for both vertical and horizontal direction.
The beam size is about 0.9mm for both vertical and horizontal direction across the longitudinal range of the translation stage.
All measurements and analysis files are saved on the online MATLAB as we have some issues with MATLAB license. To be reinstalled.
[Marc, Michael M. , Shalika]
We removed the previous birefringence readout from the imaging unit which was using PBS and several optics installed on a small breadboard.
Instead, we now use Thorlabs polcam that was aligned to the input beam.
We tuned the input QWP/HWP to reach circular polarization, then installed and aligned a polarizer to inject pure linear polarization.
While testing the polarizer alignment vs rotation, the power control HWP was mistakenly rotated sending up to about 300mW to the polcam.
It disabled itself crashing the vi but could be somehow recovered after sometimes.
It seems that the camera is still able to properly read polarization (at least linear) as the read value corresponds to the expected polarizer rotation.
This issue arised because when 2 motorized rotator controller are connected to the pc, only one is detected... For safety, after recovering the appropriate input power, we disconnected the power controller HWP.