I have put down and pulled up the first section of the south path a few times. I've developed a habbit of packing optics in at close range and we decided that this was not so great when we had plenty of space. Starting at the begining again I had another go at measuring the mode strait out of the laser. Data is attached below and z0 = 0 is referenced to the front of the laser head.
I changed the power at point 8 and there seems to be a distict change in slope there. There are two waveplates, a PBS (which I think is UV silica) and a W2 coated window that is definitly fused silica.
This data is much cleaner than earlier measurment and I'm not sure if the change in waist (for the measurment) is enought to be worried about. I will use these values for subsqutent modematching.
Horz. beam waist = 193.4873 um
Horz. beam waist position = 27.7636 mm
Vert. beam waist = 139.5525 um
Vert. beam waist position = 34.6003 mm
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