[Marc, Katsuki]

We tuned input polarization to 0deg azimuth and ellipticity with QWP and HWP.

Katrsuki-san made a 15% hydrogel and we started acquiring birefringence data.

However, the translation stage acting on the pusher was not too well fixed so it was moving a bit after every motion and also applying force on diagonal.

We used sand paper to increase the translation stage holder hole diameter and used zip tie to stabilitze it.

Then, we measured 10% hydrogel mixture at the bottom and the top of the cell container.

After small motions were nothing happen, we can see a clear linear relationship between birefringence and pusher position.

When the laser is hitting the bottom of the cell container, there is an intermediate phase where the effect is linear but smaller.

The pusher motion to force was calibrated using a kitchen scale.

data are saved in the cell birefringence folder :

#first 2 measurements below were done with pusher not too well fixed..
foldername = r'C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\cell birefringence'
#15%
filename = 'Mon, Mar 4, 2024 2-14-41 PM.txt'
#10%
filename = 'Mon, Mar 4, 2024 3-30-28 PM.txt'
#10% and better way to apply force
filename = 'Mon, Mar 4, 2024 3-56-22 PM.txt'
#same as before but laser beam close to top of box
# filename = 'Mon, Mar 4, 2024 4-30-33 PM.txt'

All measurements were made with the plastic cell container.

For the glass cell container we should use a .8 or .9 mm diameter pusher (vs 1 mm for the plastic one).