Reply To: RMS spot size interpretation

[jurgen.schmoll]

Hi Ethan,

thank you for your reply and apologies for my late reaction. I forgot to tick the "send an email when a reply is coming in"-box ... 

So the values are the transversal aberrations from the the ideal (0/0) spot location, and so they can be either positive or negative. What happens with rms spot (x+y) ? I wonder why the plot shows 8-12 micron rms spot radius, while the merit function of "rms spot (x+y)" shows only 3.9 micron. Mathematically, x+y could be negative if y>x, and it makes no sense to me for all it explains the smaller values. Should the rms (spot radius) not be more suitalbe, with the radius being the square root of (x^2 +y^2) for each lateral aberration point? Maybe I just misunderstand the expression "rms spot(x+y)" here.