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Reports until 10:14, Wednesday 02 October 2024
H1 SQZ (DetChar)
sheila.dwyer@LIGO.ORG - posted 10:14, Wednesday 02 October 2024 (80425)
OPO green losses increasing

Following up on the need to decrease the OPO pump circulating power last night (80413), I went to SQZT0 to see if I could improve the pump fiber alignment. I was only able to get a small improvement by walking the steering mirrors into the pump fiber, and also a small decrease in the rejected polarization in HAM7 by walking the half wave plate and quarter wave plate in the pump fiber path. 

The attached trend shows that since the OFI vent,the green power reflected from the OPO, in both polarizations, has been steadily increasing while the transmitted power has been constant, which means that the launched power has had to increase.  This indicates that we should try to move the OPO crystal soon.

I'm tagging Detchar here because when I went to the table I realized this morning that the lights have been on in SQZT0 since last Tuesady, 80266, they are off now as of 17:00 UTC on October 2nd.  Apologies, if there is any change in 60Hz or sidebands during this time. 

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