[Pablo and Kiwamu]

 We have measured the reflectivity of another 2" P-polarizing beam splitter (E040512-B3 SN: I0822-07) for S-polarization this morning at the OSB optics lab.
The results are :
    HR reflectivity R = 92.5 % for S-pol @ 1064 nm, 45 deg
    AR reflectivity R =  2.8 % for S-pol @ 1064 nm, 45 deg

Background :

Even though we already installed a 90% S-polarizing beam splitter on HAM1, we still thinks that this 90% might not be big enough to attenuate the reflection beam to avoid damaging the detectors. One way to increase the safety margin is to simple replace this 90% BS by one with a higher reflectivity. Because we have 90% P-pol BS in hand we simply wanted to try measuring the reflectivity with a S-polarizing beam.

Setup:

Same as the previous measurement (see alog #7817).