[Mackenzie, Evan, Paul]
Today we improved the alignment of the aux laser into HAM2, and after some searching around with the aux laser temperature control were able to observe the beat signal on the RFPD. The beat signal amplitude was around -45dBm at best, when we had 1.5V DC on the PD. I didn't check the difference between DC and AC gains for that pd, but we expect we should be able to get a significantly larger beat signal. We adjusted the aux laser alignment trying to improve the beat signal amplitude, but weren't able to get a big improvement. At this point we think that we are limited by the mode matching of the two beams: it's clear just looking at the card that there's at least a factor 2 in beam sizes at the IM4 forward trans beam path. Next step will be to make some quick mode measurements on the table and either adjust the lens currently in place or add some more to the path to get a better overlap.