The diffracted power versus ISS offset slider value was measured.
Attached is the plot for the percent diffracted power versus AOM
drive signal.

Unfortunately the plot isn't really parabolic.  Looking at the plot
it looks like the best region for the AOM drive is somewhere between
0.65 and 0.75 V.  Which represents somewhere between 8.5 and 17%.

A better characterisation of the AOM drive involves adjusting a pot
on the ISS board to better linearise the output of the multiplier
chip.  That's a somewhat iterative process between measuring the
diffracted output and adjusting the pot.

The full power of the laser was measured to be 167.5 W.