= MIR Meeting on 2020/12/30 18:00 - 19:00 =

Participants: 

=== Next meeting ===
2021 Jan 20th, 18:00 - 19:00


== Minutes ==

Birefringence R&D
 * Dr. Marco Bazzan (University of Padova, Italy; now joining MIR) gave an introduction into photo-stress tensor and polariscopes
 * we want to know how we can use our measured data on birefringence in Sapphire bulks to conclude about the internal stress physically
 * Discussion:
  * our device in TAMA seems not so different from a plane-polariscope but analytical considerations on how to extract stress-parameter (orientation of stress-symmetry axis and refraction-index difference) are necessary
  * apparently we need at least two measurements with different linear polarizations 
  * we can upgrade the existing system with λ/4 plates to construct a circular-polariscope so that we only need one measurement to get the stress-parameter. Matteo will take care on getting the necessary items

Future organization of this meeting:
 * MIR meeting becomes more official and may/should use official KAGRA zoom
 * we will start to write minutes of the meetings (--> Simon)
 * host will be Matteo

== Agenda ==