• 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