%EM Linear and circular wave propagation..
%Kenyon fig. 10.1 p.278
%Circular E wave propagating along the X axis.
%E field is along the yz plane (E1_0 z^ + E2_0 y^)
% Direction of propagation s^ = -z^ X y^ = x^
% Steven Sahyun November 10, 2014


clf();
clear;

t=0;
%max=2; %for size of graph
%x = 0;
w = 1/10;

while(1)
    
    
%wavelength = input('Wavelength (nm) = ');
lambda = 500;  % Set at 500 nm, uncomment above if you want to choose the wavelength in the program.


Ez_0 = 100; % Electric field amplitude
Ez_0 = input('Input Ez_0 Amplitude (0-100) = ');

Ey_0 = 100; % E field initially equal component
Ey_0 = input('Input Ey_0 Amplitude (0-100) = ');



phase = input('Input phase between Y and Z E components as a fraction of the wavelength (Eg.: -0.25)= ');
phase = 2*pi*phase;

k = 2*pi/lambda; %wave vector
c = 1; % speed of light

%xin = starting point for graph
xin = 0;
%zfi = ending point for graph
xfi = 1000;
x=xin:(xfi-xin)/1000:xfi; %1000 plot points

%This is to set the axes
xaxis = x*0;
yaxis = x*0;
zaxis = x*0;


for t = 1:300
    clf;
    hold on;

%Creating the E vector
Ez=Ez_0*cos(k*x - w*t); %Ez in z^ direction; propagating in x direction  - this is a 1D vector
Ey=Ey_0*cos(k*x - w*t + phase); %Ey in y^ direction; propagating in x direction - this is a 1D vector
% note the phase term.

E_tot = [0 Ey Ez]; % E_tot is a vector representing the E field but in MatLab, this is a matrix.

%plot3(x, yaxis, zaxis); % Plot propagation axis
quiver3(0,0, 0,xfi,0,0, 'r') % Plot vector showing propagation of light

% Plot EM wave
plot3(x, Ey, Ez); % Plot E field 

quiver3(0, 0, 0, 0, Ey(1), Ez(1), 'b'); %Electric Field vector

%This just sets the axes and initial view
axis([0, xfi, -100, 100, -100, 100])
%axis square;
view(-37.5+68, 30)
axis on
grid on

%0hold on
 %Label graph
 
title('EM ray propagating along the X axis.') 
xlabel('Distance in nanometers (X axis)')
ylabel('E Field (Y axis)') 
zlabel('E field (Z axis)') 
 
	M(t) = getframe;
end


%To replot function with different phases:
ch= input('Press 1 to continue, 2 to clear graph and 0 to exit: ');
if ch == 0
    break;
elseif ch == 2
    hold off;
     
else
    %
end
end