% Phasor plot
% Kenyon fig. 5.5 p. 101
% Ploting the phase diagram for the addition of two plane waves with a phase difference of phi.
% Steven Sahyun 140930

clf();

d = 5000; %slit separation in nm
lambda = 650; %wavelength in nm
k = 2*pi/lambda;
y = 2;
screen = 100; 
theta = atan(y/screen);
phi=k*d*sin(theta);
%phi = pi/4; %phase difference between the two waves.

t=0;
max=2; %for size of graph

x = 0;
w = 1/10;

for t = 1:126
    clf;
    hold on;
    E1 = cos(k*x-w*t)+i*sin(k*x-w*t); %First wave
    E2 = cos(k*x-w*t+phi)+i*sin(k*x-w*t+phi); % Second Wave
    Esum = E1+E2;
    quiver(0,0,real(E1),imag(E1)) %quiver plots a vector arrow.
    quiver(real(E1),imag(E1),real(E2),imag(E2))
    quiver(0,0,real(Esum),imag(Esum))
    

    title('Phasor Diagram for the addition of two Plane Waves');
    xlabel('Real');
    ylabel('Imaginary');
    legend('E1', 'E2', 'E=E1+E2');
	axis([-max,max,-max,max], 'square')
    
	M(t) = getframe;
end