Dhruva, Naoki, Sheila, Trent, Camilla
This afternoon we tried some SQZ optimization, left SQZ ASC on while squeezing.
Edit: Going back to 120/120 after the IFO has been locked for 2.5 hours we see a lot less frequency dependent rotation. The rest of the team is continuing PSAMS optimization now.
Dhruva measured is NLG is 17. sqzparams.opo_grTrans_setpoint_uW is at 80uW, giving us 21.4 SHG Launch. OPO temperature optimized during this measurement.
Started with 120/120 PSAMs, can see frequency dependence with SQZ angle. Able to optimize high OR low frequency, not both. BLRMs trend attached.
- ref5 20:07UTC ZMs at 150/150, seems better
- ref6 22:10UTC ZMs at 200/200, 190deg
- Around 22:15UTC we turned off the AS offset from 76407.
- ref7 22:16 ZMs at 200/200, 190deg
- ZMs at 180/180, 190deg
| BLRMS Number | Frequency (Hz) |
| 1 Red | 75 - 90 |
| 2 Orange | 120 - 150 |
| 3 Yellow | 300 - 400 |
| 4 Green | 700 - 1750 |
| 5 Blue | 1650 - 1750 |
| 6 Purple | 4600 - 4750 |
The first attachment shows the DARM with 120/120 PSAMS and different sqz angle. After 45 min NLN, we changed sqz angle from 220 deg to 190 deg. The 220 deg is good for high frequency, but bad around 100 Hz and vice versa for 190 deg. However, after 2.5 hours NLN, the squeezing at high frequency got much better and reached 5dB squeezing. This would indicate the squeezing angle rotation by thermalization of SRCL detuning.
The second attachment shows the DARM with 190deg sqz angle and different PSAMS. The 180/180 PSAMS gave flat squeezing after 45 min NLN, but we found that the sqz became flat with 120/120 PSAMS after 2.5 hour NLN so we set PSAMS at 120/120.
