###########################################################################
# Scriptfile: far_field_projecion.lsf
#
# Description:
# This file will perform far field projection and the projected far foield data
# will be written in far_field_projection.fld file.
# This fld file will be impored to overlap.lms and/or mode_expansion.fsp 
# to perform overlap and/or power coupling calculation.
# Copyright 2012, Lumerical Solutions, Inc.
###########################################################################

num=25;              # resolution

# define far field plane to image fields
x=linspace(-20e-6,20e-6,num); 
y=x;
z=1.5e-3;

# compute far field
E=farfieldexact3d("far",x,y,z); 

# select component
Ex=pinch(E,4,1); 
Ey=pinch(E,4,2);
Ez=pinch(E,4,3);

# image intensity
E2= abs(Ex)^2 + abs(Ey)^2 + abs(Ez)^2;
image(x*1e6,y*1e6,E2,"x (micron)","y (micron)","Electric field at z=1.5mm from source"); 


lambda = 650e-9;
refractive_index = 1;
z = 0; # this is z z-normal source

# now we creat a 2d surface
X = meshgridx(x,y);
Y = meshgridy(x,y);

# don't modify the following commands
dx = x(2)-x(1);
dy = y(2)-y(1);

# fill in the variables needed for createsource.lsf
include_H = 0; # 1: H fields are defined, 0: H fields defined from E fields
wavelength = lambda;
power = 1;
index = refractive_index;
axis1 = 1; # x axis
axis2 = 2; # y axis
min1 = x(1)-dx/2;
max1 = x(length(x)) + dx/2;
min2 = y(1)-dy/2;
max2 = y(length(y)) + dy/2;
depth = z;
n1 = length(x);
n2 = length(y);
sourcefilename = "ff_sourcefile";

#create the source by calling usr_create_fld.lsf
usr_create_fld;