Simple example on how to compute the power loss at a circular aperture.
# Finesse 2 example # Detecting the power loss at a mirror with # an aperture as a function of the aperture seize # Beam radius = 1mm # Andreas Freise, 13.11.2019 l l1 1 0 n1 gauss g1 l1 n1 1m -1 s s1 1 n1 n2 m m1 0.5 0.5 0 n2 n3 s s2 1 n3 n4 maxtem 0 pd refl n2 noplot refl set Pr refl re pd trans n3 noplot trans set Pt trans re func PowerLoss = 1 - $Pr - $Pt yaxis log abs xaxis m1 rap lin 0.2m 3m 100 pyterm pdf
Slightly off topic, but can use dummy variables to tune the ration between the mirror and beam radius:
var ratio 1 # define ratio as dummy variable set _ratio ratio re # this is requires for the func command func rap = $_ratio * 0.001 # compute the aperture size noplot rap # we don't want to plot the aperture size put m1 rap $rap # set the aperture xaxis ratio relsize lin 0.2 3 100 # now we can tune the ratio
Note that the second parameter in the xaxis command (‘relsize’) is just a random string when you use xaxis with a dummy variable.
Parameter handling will be much improved in Finesse 3, see for example this post.