Simon, Pengbo

This week we finished the characterization of the KAGRA-size Shinkosha sample #7.  We did several polarization maps with different incident polarization angles.( 0 degrees represents the pure p polarization)

As can be seen, both S- and P- polarization maps show an apparent offset, which is reasonable due to the birefringence effect. And the other three mixtured maps are well-matched with the incident polarization angles.

Noted that, each time when I adjusted the polarization, the DC signal keeps a relatively stable state but the AC signal seems very unstable, either goes up or goes down for a long time.