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ShalikaSingh - 19:24, Saturday 02 March 2024 (3460)Get code to link to this report
BS birefringence

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

Comments related to this report
ShalikaSingh - 20:24, Tuesday 05 March 2024 (3473)

There was issue with how data was saved. Even though there was averaging implented, there was no resetting of averging buffer after voltage change. Now, the data are being saved after the corrections.

New folder: C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Beam Splitter Calibration\20240305

Only LC, No BS:

Tue, Mar 5, 2024 7-45-18 PM.txt

Back face

transmission:

Tue, Mar 5, 2024 8-19-02 PM.txt

reflection:

Tue, Mar 5, 2024 8-03-47 PM.txt

Tue, Mar 5, 2024 8-13-04 PM.txt

Tue, Mar 5, 2024 8-16-36 PM.txt