Sheila, Camilla, Georgia

I've added some links to google docs which are useful for the VIP build to the file card for the VIP drawing, D1500302

For the alignment of SFI2 on the VIP, we will need a beam with enough power to see the reflection off of the KTP wedge which is off the Faraday sled (B:P1 in the drawing), in order to set the roll of the wedge.  After discussions with Paul and Ryan at Florida, we decided to use a beam injected from the OFI side to do the alignment of the Faraday and wedge (procedure as we discussed is currently in the VIP assembly google doc).  This allows us to have more power in the beam, compared to using the CLF transmitted through the OPO path.   It also should allow us to align the beam from the OFI side with the beam from the OPO once the Faraday is set up, setting this alignment from the OPO side would be tricky because the yaw of the KTP needs to be a specific angle, and the transmitted beam would also need to be aligned through the SFI2 appertures. 

Last week Camilla, Georgia and I set up the fiber collimator with the beam from the prometheus injecting in this path (incident on B:M4 in the drawing).  This path would have s-pol light in the normal configuration (if we were sending a beam from the filter cavity towards the OFI), but in order to send light backwards through the Faraday and get the correct beam out of the wedge, we need to inject p-pol light.  We re-arranged the path on Tuesday to use the beam transmitted from a PBS, so we are now using p-pol light on optics that are intended for s-pol.  There is a visible ghost beam off B:M4, which is E1900392, HR for s-pol best effort for p-pol. 

We initially aligned the beam to the SFI2 apperture on the OFI side easily, and saw a beam at the output.  On Tuesday Camilla and I looked more closely, and I think that we were going over the top of the apperture on the wedge side of the Faraday. We tried to walk the alignment and adjust the position of the beam on B:M3, but came to the conclusion that it will be difficult to align this beam to the two apertures from this direction.

I think that we can use a temporary mirror to imitate the Faraday, setting up a beam that is parallel to the bolt holes headed towards the wedge (this will not necessarily give us the correct alignment of B:M3, B:BS1, and B:M4).  We could use this bright beam to set the wedge roll pit and yaw, and then see it transmitted down the B path toward SFI1.  If we then swap the fiber from the prometheus back to the CLF fiber, we could use the OPO transmission to set up B:M1 and B:M2.  Using the fiber laser in the fiber collimator to inject from the OFI side to give us a guide beam, we could get a beam from the OPO with the correct incident angle on the wedge, and parallel to the bolt holes.  This beam from the OPO should then be close to the correct alignment for us to place the SFI2 sled on the platform and see a transmitted beam.