Sheila, Nutsinee, Terry,

This is an update on the progress so far on the VIP. We have aligned and mode matched both the CLF/seed 1064 path and the 532 pump path to the OPO, and are ready to think about swapping M1 for the higher green reflectivity version.  

• We have collimators which were labeled SN18 for 1064 and SN4 for 532.  Maggie measured the modes out of these collimators and posted her data here.  Terry and I also measured both wavelengths in both collimators, here, but at that time the 1064 and 532 collimators were somehow swapped (so the collimator called "supposedly for 1064" in that log is now being used for 532 nm and vice versa.).  Nutsinee also made a better measurement of the mode out of the collimator now being used for 532 in the far field here.
• The first attached photo shows the path from the 1064 collimator to M2 where it is injected into the OPO.  The distance from the collimator to the steering mirror is 173mm, the total distance from the collimator to the AR side of M2 is 270 (+/-~1) mm, from the collimator to the edge of the OPO mounting block is 226mm, and the distance from the collimator to the ROC+150mm lens (f=334mm according to this) is 41mm.  After the lens is a thin film polarizer type 2 which transmits P polarized light, followed by a half wave plate to rotate the polarization back to vertical as required for the OPO.  
• The second attachment shows the 532 pump path.  The distance from the collimator to the first steering mirror is 180mm, the total distance from the collimator to the edge of the metal block the cavity sits on is 190mm, the total distance to the AR surface of M1 is ~234mm.  The first lens is ROC+75mm (f=162.8mm) 152mm from the collimator, while the second lens is 199 mm from the collimator (19 mm from the steering mirror).  This path has a thin film polarizer and half wave plate similar to the 1064 path.  
• We scanned the cavity using the M2 PZT and a thorlabs PZT driver.  Using the free spectral range of the OPO 853.452MHz from T1700104, I did a quadratic fit of the measured 00 peaks of 1064 transmission through M1 to rescale the voltage applied to the PZT driver into resonant frequency of the OPO.  The higher order mode peak is the mode mismatch. From these four measurements the mode matching is 81.1+/- 0.2% standard error.  We did not try to optimized the mode matching of this path, but we can come back and attempt to adjust it if there is time before installation.  
• The dips in reflected power are 95.7+/-0.1% of the power off resonance, without correcting for the higher order modes.  While this is consistent with our expectation for a 99.8% reflectivity M2 and 87.2% reflectivity M1, this give us a measurement of the cavity losses which is dominated by the transmission through M1, and doesn't give us a good measurement of the OPO escape efficiency. 
• Although the documentation calls for two dichorics in the squeezing path, we had only one superpolished dichroic so we used it to separate the green and red and use 1064 HR mirrors for the rest of the squeeze path. 
• Nutsinee has and will post data from the 532nm cavity scans.