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Entry  Tue Jan 4 18:26:59 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
    Reply  Wed Jan 5 17:46:04 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
       Reply  Mon Jan 10 18:20:45 2022, Anchal, Update, BHD, Tested 2" PR2 candidates transmission 
          Reply  Tue Jan 11 15:21:16 2022, Anchal, Update, BHD, PR2 transmission calculation LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPRS_Trans_Calc.ipynb.zip
             Reply  Thu Jan 13 17:10:55 2022, Anchal, Update, BHD, PR2 transmission calculation LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPR2_Trans_Calc.ipynb.zip
                Reply  Fri Jan 14 03:07:04 2022, Koji, Update, BHD, PR2 transmission calculation 
                   Reply  Fri Jan 14 11:00:29 2022, Anchal, Update, BHD, PR2 transmission calculation 
                      Reply  Fri Jan 14 13:46:25 2022, Anchal, Update, BHD, PR2 transmission calculation updated LO_power_vs_PR2_transmission.pdfPRC_Gain_vs_PR2_transmission.pdfPR2_Trans_Calc.ipynb.zip
                         Reply  Wed Jan 19 16:22:48 2022, Anchal, Update, BHD, PR2 transmission calculation updated PR2transmissionSelectionAnalysis.pdfPR2_Trans_Calc.ipynb.zip
                            Reply  Thu Jan 20 01:48:02 2022, Koji, Update, BHD, PR2 transmission calculation updated 
Message ID: 16541     Entry time: Tue Jan 4 18:26:59 2022     Reply to this: 16543
Author: Anchal 
Type: Update 
Category: BHD 
Subject: Tested 2" PR2 candidates transmission 

I used the rejected light from the PBS after the motorized half-wave plate between PMC and IMC injection path (used for input power control to IMC) to measure the transmission of PR2 candidates. These candidates were picked from QIL (QIL/2696). Unfortunately, I don't think either of these mirrors can be used for PR2.

  Polarization Incident Power [mW] Transmitted Power [mW] Transmission [ppm]
V2-2239 & V2-2242 s-pol 940 0.015 16.0
V2-2239 & V2-2242 p-pol 935 0.015 16.0
V6-704 & V6-705 p-pol 925 21 22703

If I remember correctly, we are looking for a 2" flat mirror with a transmission of the order of 1000 ppm. The current PR2 is supposed to have less than 100 ppm transmission which would not leave enough light for LO path.

I've kept the transmission testing setup intact on the PSL table, I'll test existing PR2 and another optic (which is 0.5" thick unfortunately) tomorrow.

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