* Participants : Y. Aso, M. Eisenmann, M. Otsuka, S. Singh, K. Yamamoto, H.  Wang

* Minutes :

 * ITM polishing : 
Nikon won 1st surface pre-post polishing

 * PI update :
Optical Q simulation on-going found Q~10**12 instead of 10**9 in Kaihotsu thesis (likely 10**12 correct and typo for 10**9)
How to consider HOM vs fundamental mode Q? 
OSCAR, Finesse, SIS useful simulation tools

  * Birefringence at Mitaka
AlGaAs measurement vs angle of incidence on-going
2D measurement started  and analysis on-going

  * Birefringence at KAGRA (actually polarization sensor for DM search)
Installed s/p pol PD at TMS X/Y
some presence of birefringence
How to measure coating, ITM and ETM birefringence separately (maybe visible through change in Power or Temperature of the components?)

  * Birefringence at Virgo
Contact by Flavio about possibility that Virgo mysterious noise is from birefringence
Can BS coating induce differnt resonance condition for s and p polarization?