KAGRA MIR (Polarization)
MarcEisenmann - 13:02, Friday 03 June 2022 (2971)
Birefringence measurement of AZTEC #3

This is a report of AZTEC #3 birefringence measurements where each map had for parameters : X_center = 400.735 mm, Y_center = 122.105 mm, Z_center = 70.275 mm, with 70 mm radius.

Birefringence characterization :

Figures 1 to 6 are the usual polarization measurements, 7 to 9 summarize informations about the stress tensors and delta n and theta distributions.

The sample seems quite uniform and is now a good candidate for KAGRA (it also had quite low absorption).

 

c axis orientation estimation :

In figure 10, I tried to compute from the mean output polarization the orientation of the sample c axis.

The mean output polarization is fitted by a sine square as a function of the input polarization where errorbars represent 1 sigma uncertainty.

From this fit, it seems that if we inject 50.23 deg input polarization we should have the same at the ouput.

In order to constrain a bit more the fit I am now doing a measurement with p polarization at the input and then will start the measurement at the polarization angle that should be conserved throughout the sample.

Images attached to this report
2971_20220603055858_pol0.png 2971_20220603055902_pol15.png 2971_20220603055907_pol30.png 2971_20220603055912_pol45.png 2971_20220603055916_pol60.png 2971_20220603055921_pol75.png 2971_20220603055925_s0.png 2971_20220603055928_s1.png 2971_20220603073339_deltantheta.png 2971_20220606042202_caxis.png
Comments related to this report
MarcEisenmann - 14:03, Tuesday 07 June 2022 (2973)

There were some mistakes in the analysis so these results are not correct.

I'm also starting to doubt the way we analyze our measurements so I'm thinking to speed up the installation of the Soleil-Babinet compensator for this characterization.