I started doing a power budget for the table, but got side tracked investigating the in-loop diode that doesn't have any response.  I tried realigning onto it but got a strange response that included negative voltages.  As a result the lens isn't in place in front of the diode now, so I've blocked this path using a 10W power meter head (this path gets ~200mW so this head can easily cope).  The laser is turned off just now at the controller.

There is already a fairly large power reduction through the AOM, from 63W down to 56.6W, then down to 56.1 after the polarizer.  The PDs are getting 450mW, so even after these stages there is more than 50W going into the rest of the table.  It is pretty tricky getting power meters in becasue there isn't a lot of room, so we may not get a complete picture of the power losses.  I'll work more on this tomorrow.