Displaying report 1-1 of 1.
Reports until 12:52, Thursday 01 February 2018
H1 SQZ (SQZ)
sheila.dwyer@LIGO.ORG - posted 12:52, Thursday 01 February 2018 - last comment - 11:11, Sunday 18 February 2018(40362)
VIP aligned for 1064 and 532 before M1 swap

Sheila, Nutsinee, Terry,

This is an update on the progress so far on the VIP. We have aligned and mode matched both the CLF/seed 1064 path and the 532 pump path to the OPO, and are ready to think about swapping M1 for the higher green reflectivity version.  

Images attached to this report
Comments related to this report
nutsinee.kijbunchoo@LIGO.ORG - 17:22, Tuesday 06 February 2018 (40434)

Here's the green data (+PZT calibration). Note that the data hasn't been corrected for dark current. 

  • I did the same trick Sheila did (poly degree 2 fit to the time vs. FSR plot) to rescale the voltage applied to the PZT driver so the relationship between resonance peaks and frequency is linear.
  • The mode matching calculated from transmitted power is 66% +/-1%  
  • The dips in reflected power are 75.6% +/-0.4% of the power off resonance. Higher order modes has not been taken into account.
  • The PZT driver (Thorlabs MDT694) has an external input gain of 15V/V. This results in 22V per FSR, or 40V/um.
Images attached to this comment
nutsinee.kijbunchoo@LIGO.ORG - 11:11, Sunday 18 February 2018 (40594)

I corrected the green data for dark current as Sheila suggested. The mode matching calculated from transmitted power is now 73.5%. The dips in reflected power are 78.8% of the power off resonance. Higher order modes has not been taken into account.

Images attached to this comment
Displaying report 1-1 of 1.