sheila.dwyer@LIGO.ORG - posted 21:51, Monday 14 September 2026 - last comment - 16:31, Tuesday 15 September 2026(91903)
quick look at recovering squeezer
- Turned on the sqz laser, Marc Pirello turned on high voltage supplies.
- with the OPO dither locked on the seed, I adjusted ZM3 to get full power onto SQZT7 IR PD, didn't see light on AS port PDs this way.
- PMC transmission is normal at 660mW. SHG green power is 77mW, rather than 100mW normally, SHG launch power is 9mW max, compared to up to 30mW we normally have available.
- I tried adjusting the SHG alignment picomotors, this didn't improve the SHG transmission much.
- Filter cavity green flashes cavity modes.
Camilla and I had another look at the filter cavity alignment this afternoon. We see green flashes of 7.1 counts, where we would expect about 30 counts based on the launch power and O4 FC transmission. These slider values are in the attached screenshot. Went to SQZT7 to align the beam onto FCGS refl diode, didn't see any signal in the DC readback of that diode. However, now there are mini locks of the filter cavity on the 00 mode, so this looks like the diode is working.