In order to make finesse measurements I needed a faster (higher BW) PD in transmission of the cavity for ringdown measurements. I have installed a PDA05CF2 (note this is not rated for 775 but it is still between .1-.2 A/W responsivity at this wavelength). Because this PD is a much smaller area, it requires a lens to see any higher order mode flashes. It has been installed. The output configuration of OFC2 775 nm light has been slightly rearranged to optimize. 

I performed ringdown measurements similar to this log post. The results are seen in finesse.png. I was hoping to see a major difference in measured finesse of the cavity that had just been assembled vs one that had been on an optics table for months. The new cavity has slightly higher measurements, meaning slightly lower losses, but it is still a fair bit away from the quoted mirror specs. This corresponds to roughly 100 ppm loss per mirror vs 85 ppm loss per mirror on OFC1 vs OFC2.

It seems like the two cavities have roughly been dirtied the same amount. I think I may look into applying first contact to the superoptics while they are situated in the cavity.