[Shalika, Marc]

I had placed the HWP and QWP before Faraday Isolator previously. We removed it and now the FI is directly after the Laser. The FI transmission was optimised by tuning the polarizers to give max power output. 

Actually, we also observed that while tuning isolation, we were not having power more than 0.6mW in transmission of FI, although the incident power was 40mW. It seems that FI was not optimally mounted for the vertical polarisation of our laser. So, we rotated the FI by 90deg, correctly mounted it, and then optimised transmission in forward alignment. We didn't measure the isolation ratio again. Previous tunings had shown that it was around 40-55dB.

We placed BST11 in the steering path of LC. The high reflectance was replaced with this. The reflection of 70% goes to LC and transmission of 30% is used to monitor the input laser power + fluctuations.

Because of change of mirror with the beam sampler the beam path was modified to reach the camera. 

After proper optimisation, the QWP, HWP and input polarizer before LC was optimized to have linearly polarized light, of azimuth and ellipticity of 0+/- 0.01 deg.

The two LC were placed in series, and are now undergoing voltage scan from 0 to 25V with 5mV step size, at a temperature of 30degC.

data is here: C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Polarization states\2024021\Thu, Feb 1, 2024 5-22-37 PM.txt