On Friday, Valera and I calculated the modematching for reference cavity from AOM.
We scan the beam profile where the spot should be.
The first beam waist in the AOM is 103 um, the lens (f= 183 mm, I'm not sure if I have the focal length right) is 280 mm away.
The data is attached. The first column is marking on the rail in inches,
the second column is distance from the lens, the third and fourth column are
vertical and horizontal spot radius in micron. Note that the beam is very elliptic because of the AOM.