* Participants : 

T. Akutsu, Y. Aso, M. Eisenmann, S. Lee, M. Otsuka, H. Saint-Olive, S. Singh, K. Yamamoto

 * Topics : 

  * New ITMs :
    * Okamoto will grind the chirp close to AR side during ~ 1 month
    * Nikon will spend 2 weeks/surface to pre-polish each surface to remove scratches
    * overall 10 weeks delay expected (now waiting for quotation) but should be fine with respect to LMA schedule for coating
  * Birefringence measurement :
    * can use pair of LCs to measure Jones matrix, diattenuation and birefringence of samples in transmission and reflection
    * now checking long term stability and improvement of uncertainty
    * is it interesting to measure KAGRA BS properties? if so do we have witness sample?
  * 10years plan : 
    * iLM/LMA can grow 30cm diameter sapphire with some(?) down to 20-30ppm/cm absorption. They are now trying to reduce birefringence
    * Jerome Degallaix (LMA) will be invited at an upcomming meeting
    * AZTEC CEO changed and Mr. Hong who grown our substrates is creating his own start-up. Sungho purchase 30mm and 60mm new samples from AZTEC to be characterized.
  * PI simulations
    * Otsuka plans to study PI and their mitigation for KAGRA
    * Kaihotsu and Kaido thesis presents such investigation : worth trying to repeat this simulation with bonding layers and different aspect-ratios?
  * next meeting : 
    * Switch to 2 meetings/month
    * next meeting on June 19th