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Entry  Thu Feb 7 17:27:53 2019, Koji, Summary, Tip-TIlt, Five FiveNine Optics Optics delivered 
    Reply  Fri Feb 8 00:20:56 2019, gautam, Summary, Tip-TIlt, Five FiveNine Optics Optics delivered 
       Reply  Fri Feb 8 20:35:57 2019, gautam, Summary, Tip-TIlt, Coating spec specRefl.pdfAoIscan.pdf
Message ID: 14444     Entry time: Fri Feb 8 20:35:57 2019     In reply to: 14442
Author: gautam 
Type: Summary 
Category: Tip-TIlt 
Subject: Coating spec 

[Attachment #1]: Computed spectral power transmissivity (according to my model) for the coating design at a few angles of incidence. Behavior lines up well with what FNO measured, although I get a transmission that is slightly lower than measured at 45 degrees. I suspect this is because of slight changes in the dispersion relation assumed and what was used for the coating in reality.

[Attachment #2]: Similar information as Attachment #1, but with the angle of incidence as the independent parameter in a continuous sweep. 

Conclusion: The coating behaves in a way that is in reasonable agreement with our model. At 41.1 degrees, which is what the PR3 angle of incidence will be, T<50 ppm, which was what we specified. The larger range of angles was included because originally, we thought of using this optic as a substitute for SR3 as well. But I claim that for the shorter SRC (signal recycling as opposed to RSE), we will not end up using the new optic, but rather go for the G&H mirror. In any case, as Koji pointed out, ~50 ppm extra loss in the RC will not severely limit the recycling gain. Such large variation was not seen in the MC analysis because we only varied the angle of incidence by +/- 0.5 degrees about the nominal design value of 41.1 degrees.

Attachment 1: specRefl.pdf  17 kB  | Hide | Hide all
Attachment 2: AoIscan.pdf  17 kB  | Hide | Hide all
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