closeall;
clear;

E = getresult('field','E');
Ex = E.Ex;
Ez = E.Ez;
y = E.y;

# track the TE fraction in side the rotator
TE_frac = matrix(length(y));
for (i=1:length(y)){
  Ex_slice = pinch(Ex,2,i);
  Ez_slice = pinch(Ez,2,i);
  TE_frac(i) = abs(Ex_slice)^2/(abs(Ex_slice)^2+abs(Ez_slice)^2);
}
plot(y*1e6,TE_frac,'y (um)','TE Fraction');

# find the distance (d) corresponding to angle of rotation (beta) = 45 degrees
ind = find(TE_frac,0.5); # 45 degrees correspond to TE fraction of 0.5
?d = y(ind)-y(1); # distance