Vicky and Naoki aligned the pump ISS AOM 2 weeks ago: 79993, since then it has been steadily drifting (screenshot), such that it looks like it will rail in the next day or so. I went to the table to see if I could adjust the alignment.

start: 52 mW incident on AOM, set drive to 0V, measure 41mW in 0th order beam (78%).  set drive to 5V, 12mW in 1st order beam (23%) and 28mW in 0th order beam.

I tried several rounds of translating and yawing or pitching the AOM, alternating between 0V and 5V drive.  At one point I misaligned the SHG steering mirror with a pico because I was using too long a wrench, so tweaked that up to bring the SHG output back to 75mW, then brought some knobs to continue AOM alignment.  I was able to get 100% throughput or close with 0V drive a few times, but when I looked at where the beams were on the apertures they were obviously off center in yaw for these good throughputs.  When the beams looked more centered on the apertures the throughputs were more like 80%.  I also several times aligned to increase the diffracted power but caused the beam shape to look obviously clipped on the card.

In the end I SAW 15 mW in the diffracted beam with a round beam quality and looking roughly centered on the apertures.  I decided to quit here, and then realized that the input power had increased so that this is only mediocre AOM alignment, similar efficiency to how it started the day.   31.7 mW 0th order, 15.2mW in 1st order with 5V drive (24%), beam quality looks round, 0V drive, 47.2 mW in oth order beam, 63mW input power (75%).  

With the OPO in down, I realinged the pump fiber looking at OPO REFL, and also adjusted the wave plate for the SHG rejected path to minimize the rejected power.  After these, the ISS locked at the nominal set point of 80uW transmitted through the OPO with 3V drive signal, since I've closed up the table this is drifting up, to now 5.4V. 

So the ISS should be in better shape that it was before I started, although the AOM alignment is not improved, the fiber alignment, half wave plate adjustment, and drifts are helping. I think it would make sense to take a beam profiler out to the table and measure the beam size at the AOM, there should be space for a couple of measurements.  On a card the beam looks like it is as large as the apertures.