Sheila, Nutsinee, Terry, Dan Brown, TVo

To get an idea of the mode-matching from the OPO to the OMC, we wanted to do a beam profile measurement of the squeezer and use Alamode to fit the data points.  The hope is that the fit will match a Finesse model that includes the squeezer path from the output of the OPO, through the two lenses, ZM1/ZM2, and into the Faraday.  Then the beam reflects off of SRM HR surface and propagates to the OMC. 

The squeezer crew was able to take profiling measurements between OM2 and OM3 with the nanoscan using a pick-off mirror. They repeated this for three positions of the lens on the VOPO translation stage which allows for about +/- 2cm in travel.  The translation stage position that moved the lens closest to the VOPO has the best overlap estimate with the OMC at about 83% (using alamode) which means it's possible that we have to move the translation stage on the breadboard to get better results.  It's clear that we should move the lens+translation stage closer to the VOPO, which will move the waist location into the right spot, but this will alter the waist size.  If our model is correct, we can estimate the amount of mode-mismatch if we have to live with this lens positioning.

To double check our distances to the , which is not clear because the OMC is covered up with the shroud, we measured the OMC_REFL beam as well as the beam coming right after ZM1.  One thing that is quite odd, is that the beam was pretty astigmatic ~18% on some of the measurements.  This was not seen in the previous measurement but was seen when we've measured the IFO beam profile.  However, rotating the profiler didn't change the effect so it might be real.

To do:

- OMC PZT scan with Sqz beam this will allow use to double check our mode-matching estimate.

- Hammer on the model a bit more to get real-world measurements, Finesse, and Alamode to match up.