#############################################################
# scriptfile: plane_4layer.lsf
#
# This file calculates the reflection spectrum for
# a 4-layer dielectric stack for a given polarization ( split-field formulation
# and broadband source) and
# compares to the analytic result.
#
# Copyright 2015, Lumerical Solutions, Inc.
#############################################################
run;

R =- transmission("R");
T = transmission("T"); 

pol = getnamed("Source1","polarization angle");
theta = getnamed("Source1","angle theta");
f = getdata("R","f");
fmin=min(f);
fmax=max(f);

n = matrix(4);
d = matrix(4);

# define the indices and layer thicknesses
n(1) = 1;       
n(2) = 1.5;
n(3) = 2.5;
n(4) = 1.5;
d(1) = 1; #does not matter
d(2) = .5e-6; # layer thickness
d(3) = .8e-6; # layer thickness
d(4) = 9e-6; #does not matter since n(4) is real

T_theory=T*0;
RT_Theory = stackrt(n,d,f,theta);
if(pol==90){
T_theory=RT_Theory.Ts;}
if(pol==0){
T_theory=RT_Theory.Tp;}

ma=getnamed("FDTD","mesh accuracy");
plot(c/f*1e6,T,T_theory,"wavelength um","T ","incident angle "+num2str(theta)+"deg mesh accuracy "+num2str(ma)+"for pol="+num2str(pol)); 
legend("Sim","Theory");