I have set the laser to emit atleast 100mW. As such the power reaching the LC was 8-9mW. The mirror infront of the LC path was replaced with a 50:50 BS 10Q20HBS.33S. Now, the power is around 4mW. The input polarization before LC was tuned to be around 0+/-0.004deg in azimuth, and 0+/-0.003deg ellipticity.

An input polarizer was kept infront of the setup. In the past, sometimes the polarization changes overtime. So, for historical reasons, I kept the input polarizer back. After pol, azi 0+/-0.002 and ell 0+/-0.004 deg.

To estimate BS birefringence, LC is bein used as in polarimetry setup.

The BS Jones matrix has 4 parameters. Hence, 8 unknowns, taking real and imaginary parts into account for each element.

The BS was kept on removable magnetic mount after the pair of LC. The LC1 was scanned in voltage range 0 to 25V and LC2 from 0-5V, each with 1V step. This leaves us with atleast 8 to 10 measurements to create 8 equations. The measurements were taken with averaging of 10 order.

Calibration of BS back face

Measurement foldername : C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Beam Splitter Calibration\20242902

1. Modulation from LC, without BS.

C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Beam Splitter Calibration\20242902\

Fri, Mar 1, 2024 3-53-37 PM.txt

2. The camera is placed in the transmission of the BS.

filename: Fri, Mar 1, 2024 5-55-12 PM.txt

3. Camera in reflection of BS. The measurements were taken by removing BS 3 times. 

filename:

Fri, Mar 1, 2024 6-23-25 PM.txt

Fri, Mar 1, 2024 6-26-41 PM.txt

Fri, Mar 1, 2024 6-29-09 PM.txt