BIGFOOT (Cavity)
ShalikaSingh - 21:07, Monday 12 June 2023 (3275)
LC fast axis measurement Finalised

We were able to align LC perfectly to its axis.

1. We were having issues with our input polarization. It was observed that it didn't remain linear over long time period even though it was tuned using HWP and QWP at the start. So we placed a GT10C Thorlabs polarizer. The ellipticity after the polarizer was 0.09deg and power was around 1mW.
 
2. We fine-tuned our input polarization using HWP and QWP after it too to obtain linear polarization which remained undeviated over several hours of measurement.
 
3. The fast axis was measured and found to be 183.63deg so we rotated by 3.63 degrees and measured again to get Fig 2.
 
4. LC 2 is aligned with its fast axis and we obtained the final alignment of 179.96+/-0.39deg as shown in Fig 2 and Fig 3.
 
The position of LC as 3.63-0.04=3.59 degree has been finalised for now.
 
Specs:
LC temperature=30 deg
measurement resolution=13 deg
folder name
Fig 1--r'C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\LC2_calibration data\fast axis 15'
Fig 2--r'C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\LC2_calibration data\fast axis 16'
Images attached to this report
3275_20230612140738_lc2fastaxis150.png 3275_20230612140744_lc2fastaxis.png 3275_20230612140751_orientation21v.png