- The cable for the beat note was disconnected from the frequency counter and reconnected to the spectrum analyzer.
- PMC/IMC had not been locked for 8 hours.
- PMC was relocked.
- IMC got immediately relocked. Today IMC relocks very fast.
- Went to the ETMX table. Aligned the oplev beam on the QPD
- The X end green beam was realigned to the cavity.
I can feel that the two mirrors provides quite independent alignment adjustment. VERY NICE.
Green TRX: without PSL Green - 0.612, with PSL green - 0.725
I can clearly see that the mode matching is not ideal. All the higher modes are LG modes!
The input mode is very round.
- Arm cavities were aligned by ASS
- Tested ASX. PZT2 Pitch/Yaw servos run with the previous setting. We still can maximize the transmission by touching PZT1.
- Now Eric joined the activity.
- Once the beam is aligned what we could lock was LG00/10/20/30.
We measured the power in LGn0 modes
This suggests that the mode-matching ratio is something like 70%
- Q is aligning the PMC. PMC transmission prev 0.783. Basically we could not improve it.
We thought this number can go up to ~0.82 or even ~0.84. We wonder if this comes from the decay of the laser power or reduced visibility?